use == and != to enable handling null/undefined

lib/runtime/dart/async.js

 var async;
 (function(exports) {
   'use strict';
   // Function _invokeErrorHandler: (Function, Object, StackTrace) → dynamic
   function _invokeErrorHandler(errorHandler, error, stackTrace) {
     if (dart.is(errorHandler, ZoneBinaryCallback)) {
       return dart.dinvokef(errorHandler, error, stackTrace);
     } else {
       return dart.dinvokef(errorHandler, error);
     }
@@ skipping 14 matching lines @@
     }
     toString() {
       return dart.as(dart.dinvoke(this.error, 'toString'), core.String);
     }
   }
   class _UncaughtAsyncError extends AsyncError {
     _UncaughtAsyncError(error, stackTrace) {
       super.AsyncError(error, _UncaughtAsyncError[_getBestStackTrace](error, stackTrace));
     }
     static [_getBestStackTrace](error, stackTrace) {
-      if (stackTrace !== null)
+      if (stackTrace != null)
         return stackTrace;
       if (dart.is(error, core.Error)) {
         return dart.as(dart.dload(error, 'stackTrace'), core.StackTrace);
       }
       return null;
     }
     toString() {
       let result = `Uncaught Error: ${this.error}`;
-      if (this.stackTrace !== null) {
+      if (this.stackTrace != null) {
         result = `\nStack Trace:\n${this.stackTrace}`;
       }
       return result;
     }
   }
   let _controller = Symbol('_controller');
   let _createSubscription = Symbol('_createSubscription');
   let _onListen = Symbol('_onListen');
   let _addError = Symbol('_addError');
   let _completeError = Symbol('_completeError');
@@ skipping 13 matching lines @@
             controller._closeUnchecked();
           }).bind(this)});
         return controller.stream;
       }
       fromIterable(data) {
         return new _GeneratedStreamImpl(() => new _IterablePendingEvents(data));
       }
       periodic(period, computation) {
         if (computation === void 0)
           computation = null;
-        if (computation === null)
+        if (computation == null)
           computation = dart.closureWrap((i) => null, "(int) → T");
         let timer = null;
         let computationCount = 0;
         let controller = null;
         let watch = new core.Stopwatch();
         // Function sendEvent: () → void
         function sendEvent() {
           watch.reset();
           let data = computation(((x) => computationCount = dart.notNull(x) + 1, x)(computationCount));
           controller.add(data);
         }
         // Function startPeriodicTimer: () → void
         function startPeriodicTimer() {
-          dart.assert(timer === null);
+          dart.assert(timer == null);
           timer = new Timer.periodic(period, (timer) => {
             sendEvent();
           });
         }
         controller = new StreamController({sync: true, onListen: (() => {
             watch.start();
             startPeriodicTimer();
           }).bind(this), onPause: (() => {
             timer.cancel();
             timer = null;
             watch.stop();
           }).bind(this), onResume: (() => {
-            dart.assert(timer === null);
+            dart.assert(timer == null);
             let elapsed = watch.elapsed;
             watch.start();
             timer = new Timer(period['-'](elapsed), () => {
               timer = null;
               startPeriodicTimer();
               sendEvent();
             });
           }).bind(this), onCancel: (() => {
-            if (timer !== null)
+            if (timer != null)
               timer.cancel();
             timer = null;
           }).bind(this)});
         return controller.stream;
       }
       eventTransformed(source, mapSink) {
         return dart.as(new _BoundSinkStream(source, dart.closureWrap(mapSink, "(EventSink<dynamic>) → EventSink")), Stream$(T));
       }
       get isBroadcast() {
         return false;
@@ skipping 61 matching lines @@
           subscription = this.listen(((event) => {
             let newStream = null;
             try {
               newStream = convert(event);
             } catch (e) {
               let s = dart.stackTrace(e);
               controller.addError(e, s);
               return;
             }
 
-            if (newStream !== null) {
+            if (newStream != null) {
               subscription.pause();
               controller.addStream(newStream).whenComplete(subscription.resume);
             }
           }).bind(this), {onError: dart.as(eventSink[_addError], core.Function), onDone: controller.close});
         }
         if (this.isBroadcast) {
           controller = new StreamController.broadcast({onListen: onListen, onCancel: (() => {
               subscription.cancel();
             }).bind(this), sync: true});
         } else {
@@ skipping 285 matching lines @@
         let defaultValue = opts && 'defaultValue' in opts ? opts.defaultValue : null;
         let future = new _Future();
         let subscription = null;
         subscription = this.listen((value) => {
           _runUserCode(() => test(value), (isMatch) => {
             if (isMatch) {
               _cancelAndValue(subscription, future, value);
             }
           }, dart.as(_cancelAndErrorClosure(subscription, future), dart.throw_("Unimplemented type (dynamic, StackTrace) → dynamic")));
         }, {onError: future[_completeError], onDone: (() => {
-            if (defaultValue !== null) {
+            if (defaultValue != null) {
               _runUserCode(defaultValue, future[_complete], future[_completeError]);
               return;
             }
             try {
               throw _internal.IterableElementError.noElement();
             } catch (e) {
               let s = dart.stackTrace(e);
               _completeWithErrorCallback(future, e, s);
             }
 
           }).bind(this), cancelOnError: true});
         return future;
       }
       lastWhere(test, opts) {
         let defaultValue = opts && 'defaultValue' in opts ? opts.defaultValue : null;
         let future = new _Future();
         let result = null;
         let foundResult = false;
         let subscription = null;
         subscription = this.listen((value) => {
-          _runUserCode(() => true === test(value), (isMatch) => {
+          _runUserCode(() => true == test(value), (isMatch) => {
             if (isMatch) {
               foundResult = true;
               result = value;
             }
           }, dart.as(_cancelAndErrorClosure(subscription, future), dart.throw_("Unimplemented type (dynamic, StackTrace) → dynamic")));
         }, {onError: future[_completeError], onDone: (() => {
             if (foundResult) {
               future._complete(result);
               return;
             }
-            if (defaultValue !== null) {
+            if (defaultValue != null) {
               _runUserCode(defaultValue, future[_complete], future[_completeError]);
               return;
             }
             try {
               throw _internal.IterableElementError.noElement();
             } catch (e) {
               let s = dart.stackTrace(e);
               _completeWithErrorCallback(future, e, s);
             }
 
           }).bind(this), cancelOnError: true});
         return future;
       }
       singleWhere(test) {
         let future = new _Future();
         let result = null;
         let foundResult = false;
         let subscription = null;
         subscription = this.listen((value) => {
-          _runUserCode(() => true === test(value), (isMatch) => {
+          _runUserCode(() => true == test(value), (isMatch) => {
             if (isMatch) {
               if (foundResult) {
                 try {
                   throw _internal.IterableElementError.tooMany();
                 } catch (e) {
                   let s = dart.stackTrace(e);
                   _cancelAndErrorWithReplacement(subscription, future, e, s);
                 }
 
                 return;
@@ skipping 17 matching lines @@
           }).bind(this), cancelOnError: true});
         return future;
       }
       elementAt(index) {
         if (dart.notNull(!(typeof index == 'number')) || dart.notNull(index) < 0)
           throw new core.ArgumentError(index);
         let future = new _Future();
         let subscription = null;
         let elementIndex = 0;
         subscription = this.listen((value) => {
-          if (index === elementIndex) {
+          if (index == elementIndex) {
             _cancelAndValue(subscription, future, value);
             return;
           }
           elementIndex = 1;
         }, {onError: future[_completeError], onDone: (() => {
             future._completeError(new core.RangeError.index(index, this, "index", null, elementIndex));
           }).bind(this), cancelOnError: true});
         return future;
       }
       timeout(timeLimit, opts) {
@@ skipping 18 matching lines @@
           timer = zone.createTimer(timeLimit, dart.as(timeout, dart.throw_("Unimplemented type () → void")));
         }
         // Function onDone: () → void
         function onDone() {
           timer.cancel();
           controller.close();
         }
         // Function onListen: () → void
         function onListen() {
           zone = Zone.current;
-          if (onTimeout === null) {
+          if (onTimeout == null) {
             timeout = (() => {
               controller.addError(new TimeoutException("No stream event", timeLimit), null);
             }).bind(this);
           } else {
             onTimeout = dart.closureWrap(zone.registerUnaryCallback(onTimeout), "(EventSink<dynamic>) → void");
             let wrapper = new _ControllerEventSinkWrapper(null);
             timeout = (() => {
               wrapper[_sink] = controller;
               zone.runUnaryGuarded(onTimeout, wrapper);
               wrapper[_sink] = null;
@@ skipping 147 matching lines @@
         this[_onData] = null;
         this[_onError] = null;
         this[_onDone] = null;
         this[_cancelFuture] = null;
         this[_pending] = null;
         this.onData(onData);
         this.onError(onError);
         this.onDone(onDone);
       }
       [_setPendingEvents](pendingEvents) {
-        dart.assert(this[_pending] === null);
-        if (pendingEvents === null)
+        dart.assert(this[_pending] == null);
+        if (pendingEvents == null)
           return;
         this[_pending] = pendingEvents;
         if (!dart.notNull(pendingEvents.isEmpty)) {
           this[_state] = _BufferingStreamSubscription[_STATE_HAS_PENDING];
           this[_pending].schedule(this);
         }
       }
       [_extractPending]() {
         dart.assert(this[_isCanceled]);
         let events = this[_pending];
         this[_pending] = null;
         return events;
       }
       onData(handleData) {
-        if (handleData === null)
+        if (handleData == null)
           handleData = dart.closureWrap(_nullDataHandler, "(T) → void");
         this[_onData] = dart.closureWrap(this[_zone].registerUnaryCallback(handleData), "(T) → void");
       }
       onError(handleError) {
-        if (handleError === null)
+        if (handleError == null)
           handleError = _nullErrorHandler;
         this[_onError] = _registerErrorHandler(handleError, this[_zone]);
       }
       onDone(handleDone) {
-        if (handleDone === null)
+        if (handleDone == null)
           handleDone = _nullDoneHandler;
         this[_onDone] = this[_zone].registerCallback(handleDone);
       }
       pause(resumeSignal) {
         if (resumeSignal === void 0)
           resumeSignal = null;
         if (this[_isCanceled])
           return;
         let wasPaused = this[_isPaused];
         let wasInputPaused = this[_isInputPaused];
         this[_state] = dart.notNull(this[_state]) + dart.notNull(_BufferingStreamSubscription[_STATE_PAUSE_COUNT]) | dart.notNull(_BufferingStreamSubscription[_STATE_INPUT_PAUSED]);
-        if (resumeSignal !== null)
+        if (resumeSignal != null)
           resumeSignal.whenComplete(this.resume);
-        if (!dart.notNull(wasPaused) && dart.notNull(this[_pending] !== null))
+        if (!dart.notNull(wasPaused) && dart.notNull(this[_pending] != null))
           this[_pending].cancelSchedule();
         if (!dart.notNull(wasInputPaused) && !dart.notNull(this[_inCallback]))
           this[_guardCallback](this[_onPause]);
       }
       resume() {
         if (this[_isCanceled])
           return;
         if (this[_isPaused]) {
           this[_decrementPauseCount]();
           if (!dart.notNull(this[_isPaused])) {
@@ skipping 22 matching lines @@
         this[_onDone] = (() => {
           result._complete(futureValue);
         }).bind(this);
         this[_onError] = ((error, stackTrace) => {
           this.cancel();
           result._completeError(error, dart.as(stackTrace, core.StackTrace));
         }).bind(this);
         return result;
       }
       get [_isInputPaused]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_INPUT_PAUSED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_INPUT_PAUSED])) != 0;
       }
       get [_isClosed]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CLOSED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CLOSED])) != 0;
       }
       get [_isCanceled]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CANCELED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CANCELED])) != 0;
       }
       get [_waitsForCancel]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_WAIT_FOR_CANCEL])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_WAIT_FOR_CANCEL])) != 0;
       }
       get [_inCallback]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_IN_CALLBACK])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_IN_CALLBACK])) != 0;
       }
       get [_hasPending]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_HAS_PENDING])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_HAS_PENDING])) != 0;
       }
       get [_isPaused]() {
         return dart.notNull(this[_state]) >= dart.notNull(_BufferingStreamSubscription[_STATE_PAUSE_COUNT]);
       }
       get [_canFire]() {
         return dart.notNull(this[_state]) < dart.notNull(_BufferingStreamSubscription[_STATE_IN_CALLBACK]);
       }
       get [_mayResumeInput]() {
-        return !dart.notNull(this[_isPaused]) && (dart.notNull(this[_pending] === null) || dart.notNull(this[_pending].isEmpty));
+        return !dart.notNull(this[_isPaused]) && (dart.notNull(this[_pending] == null) || dart.notNull(this[_pending].isEmpty));
       }
       get [_cancelOnError]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CANCEL_ON_ERROR])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BufferingStreamSubscription[_STATE_CANCEL_ON_ERROR])) != 0;
       }
       get isPaused() {
         return this[_isPaused];
       }
       [_cancel]() {
         this[_state] = _BufferingStreamSubscription[_STATE_CANCELED];
         if (this[_hasPending]) {
           this[_pending].cancelSchedule();
         }
         if (!dart.notNull(this[_inCallback]))
@@ skipping 42 matching lines @@
       }
       [_onResume]() {
         dart.assert(!dart.notNull(this[_isInputPaused]));
       }
       [_onCancel]() {
         dart.assert(this[_isCanceled]);
         return null;
       }
       [_addPending](event) {
         let pending = dart.as(this[_pending], _StreamImplEvents);
-        if (this[_pending] === null)
+        if (this[_pending] == null)
           pending = this[_pending] = new _StreamImplEvents();
         pending.add(event);
         if (!dart.notNull(this[_hasPending])) {
           this[_state] = _BufferingStreamSubscription[_STATE_HAS_PENDING];
           if (!dart.notNull(this[_isPaused])) {
             this[_pending].schedule(this);
           }
         }
       }
       [_sendData](data) {
@@ skipping 71 matching lines @@
           if (dart.notNull(this[_isInputPaused]) && dart.notNull(this[_mayResumeInput])) {
             this[_state] = ~dart.notNull(_BufferingStreamSubscription[_STATE_INPUT_PAUSED]);
           }
         }
         while (true) {
           if (this[_isCanceled]) {
             this[_pending] = null;
             return;
           }
           let isInputPaused = this[_isInputPaused];
-          if (wasInputPaused === isInputPaused)
+          if (wasInputPaused == isInputPaused)
             break;
           this[_state] = _BufferingStreamSubscription[_STATE_IN_CALLBACK];
           if (isInputPaused) {
             this[_onPause]();
           } else {
             this[_onResume]();
           }
           this[_state] = ~dart.notNull(_BufferingStreamSubscription[_STATE_IN_CALLBACK]);
           wasInputPaused = isInputPaused;
         }
@@ skipping 39 matching lines @@
         this[_eventState] = null;
         this[_next] = null;
         this[_previous] = null;
         super._ControllerSubscription(dart.as(controller, _StreamControllerLifecycle$(T)), onData, onError, onDone, cancelOnError);
         this[_next] = this[_previous] = this;
       }
       get [_controller]() {
         return dart.as(super[_controller], _BroadcastStreamController);
       }
       [_expectsEvent](eventId) {
-        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_EVENT_ID])) === eventId;
+        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_EVENT_ID])) == eventId;
       }
       [_toggleEventId]() {
         this[_eventState] = _BroadcastSubscription[_STATE_EVENT_ID];
       }
       get [_isFiring]() {
-        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_FIRING])) !== 0;
+        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_FIRING])) != 0;
       }
       [_setRemoveAfterFiring]() {
         dart.assert(this[_isFiring]);
         this[_eventState] = _BroadcastSubscription[_STATE_REMOVE_AFTER_FIRING];
       }
       get [_removeAfterFiring]() {
-        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_REMOVE_AFTER_FIRING])) !== 0;
+        return (dart.notNull(this[_eventState]) & dart.notNull(_BroadcastSubscription[_STATE_REMOVE_AFTER_FIRING])) != 0;
       }
       [_onPause]() {}
       [_onResume]() {}
     }
     _BroadcastSubscription._STATE_EVENT_ID = 1;
     _BroadcastSubscription._STATE_FIRING = 2;
     _BroadcastSubscription._STATE_REMOVE_AFTER_FIRING = 4;
     return _BroadcastSubscription;
   });
   let _BroadcastSubscription = _BroadcastSubscription$(dart.dynamic);
@@ skipping 28 matching lines @@
         this[_doneFuture] = null;
         this[_next] = this[_previous] = this;
       }
       get stream() {
         return new _BroadcastStream(this);
       }
       get sink() {
         return new _StreamSinkWrapper(this);
       }
       get isClosed() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_CLOSED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_CLOSED])) != 0;
       }
       get isPaused() {
         return false;
       }
       get hasListener() {
         return !dart.notNull(this[_isEmpty]);
       }
       get [_hasOneListener]() {
         dart.assert(!dart.notNull(this[_isEmpty]));
         return core.identical(this[_next][_next], this);
       }
       get [_isFiring]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_FIRING])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_FIRING])) != 0;
       }
       get [_isAddingStream]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_ADDSTREAM])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_ADDSTREAM])) != 0;
       }
       get [_mayAddEvent]() {
         return dart.notNull(this[_state]) < dart.notNull(_BroadcastStreamController[_STATE_CLOSED]);
       }
       [_ensureDoneFuture]() {
-        if (this[_doneFuture] !== null)
+        if (this[_doneFuture] != null)
           return this[_doneFuture];
         return this[_doneFuture] = new _Future();
       }
       get [_isEmpty]() {
         return core.identical(this[_next], this);
       }
       [_addListener](subscription) {
         dart.assert(core.identical(subscription[_next], subscription));
         subscription[_previous] = this[_previous];
         subscription[_next] = this;
         this[_previous][_next] = subscription;
         this[_previous] = subscription;
         subscription[_eventState] = dart.notNull(this[_state]) & dart.notNull(_BroadcastStreamController[_STATE_EVENT_ID]);
       }
       [_removeListener](subscription) {
         dart.assert(core.identical(subscription[_controller], this));
         dart.assert(!dart.notNull(core.identical(subscription[_next], subscription)));
         let previous = subscription[_previous];
         let next = subscription[_next];
         previous[_next] = next;
         next[_previous] = previous;
         subscription[_next] = subscription[_previous] = subscription;
       }
       [_subscribe](onData, onError, onDone, cancelOnError) {
         if (this.isClosed) {
-          if (onDone === null)
+          if (onDone == null)
             onDone = _nullDoneHandler;
           return new _DoneStreamSubscription(onDone);
         }
         let subscription = new _BroadcastSubscription(this, onData, onError, onDone, cancelOnError);
         this[_addListener](dart.as(subscription, _BroadcastSubscription$(T)));
         if (core.identical(this[_next], this[_previous])) {
           _runGuarded(this[_onListen]);
         }
         return dart.as(subscription, StreamSubscription$(T));
       }
@@ skipping 26 matching lines @@
           throw this[_addEventError]();
         this[_sendData](data);
       }
       addError(error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         error = _nonNullError(error);
         if (!dart.notNull(this[_mayAddEvent]))
           throw this[_addEventError]();
         let replacement = Zone.current.errorCallback(error, stackTrace);
-        if (replacement !== null) {
+        if (replacement != null) {
           error = _nonNullError(replacement.error);
           stackTrace = replacement.stackTrace;
         }
         this[_sendError](error, stackTrace);
       }
       close() {
         if (this.isClosed) {
-          dart.assert(this[_doneFuture] !== null);
+          dart.assert(this[_doneFuture] != null);
           return this[_doneFuture];
         }
         if (!dart.notNull(this[_mayAddEvent]))
           throw this[_addEventError]();
         this[_state] = _BroadcastStreamController[_STATE_CLOSED];
         let doneFuture = this[_ensureDoneFuture]();
         this[_sendDone]();
         return doneFuture;
       }
       get done() {
@@ skipping 93 matching lines @@
         this[_forEachListener](((subscription) => {
           subscription._addError(error, stackTrace);
         }).bind(this));
       }
       [_sendDone]() {
         if (!dart.notNull(this[_isEmpty])) {
           this[_forEachListener](dart.closureWrap(((subscription) => {
             subscription._close();
           }).bind(this), "(_BufferingStreamSubscription<T>) → void"));
         } else {
-          dart.assert(this[_doneFuture] !== null);
+          dart.assert(this[_doneFuture] != null);
           dart.assert(this[_doneFuture][_mayComplete]);
           this[_doneFuture]._asyncComplete(null);
         }
       }
     }
     return _SyncBroadcastStreamController;
   });
   let _SyncBroadcastStreamController = _SyncBroadcastStreamController$(dart.dynamic);
   let _AsyncBroadcastStreamController$ = dart.generic(function(T) {
     class _AsyncBroadcastStreamController extends _BroadcastStreamController$(T) {
@@ skipping 12 matching lines @@
           subscription._addPending(new _DelayedError(error, stackTrace));
         }
       }
       [_sendDone]() {
         if (!dart.notNull(this[_isEmpty])) {
           for (let link = this[_next]; !dart.notNull(core.identical(link, this)); link = link[_next]) {
             let subscription = dart.as(link, _BroadcastSubscription$(T));
             subscription._addPending(new _DelayedDone());
           }
         } else {
-          dart.assert(this[_doneFuture] !== null);
+          dart.assert(this[_doneFuture] != null);
           dart.assert(this[_doneFuture][_mayComplete]);
           this[_doneFuture]._asyncComplete(null);
         }
       }
     }
     return _AsyncBroadcastStreamController;
   });
   let _AsyncBroadcastStreamController = _AsyncBroadcastStreamController$(dart.dynamic);
   let _addPendingEvent = Symbol('_addPendingEvent');
   let _AsBroadcastStreamController$ = dart.generic(function(T) {
     class _AsBroadcastStreamController extends _SyncBroadcastStreamController$(T) {
       _AsBroadcastStreamController(onListen, onCancel) {
         this[_pending] = null;
         super._SyncBroadcastStreamController(onListen, onCancel);
       }
       get [_hasPending]() {
-        return dart.notNull(this[_pending] !== null) && !dart.notNull(this[_pending].isEmpty);
+        return dart.notNull(this[_pending] != null) && !dart.notNull(this[_pending].isEmpty);
       }
       [_addPendingEvent](event) {
-        if (this[_pending] === null) {
+        if (this[_pending] == null) {
           this[_pending] = new _StreamImplEvents();
         }
         this[_pending].add(event);
       }
       add(data) {
         if (!dart.notNull(this.isClosed) && dart.notNull(this[_isFiring])) {
           this[_addPendingEvent](new _DelayedData(data));
           return;
         }
         super.add(data);
@@ skipping 42 matching lines @@
     class _DoneSubscription extends core.Object {
       _DoneSubscription() {
         this[_pauseCount] = 0;
       }
       onData(handleData) {}
       onError(handleError) {}
       onDone(handleDone) {}
       pause(resumeSignal) {
         if (resumeSignal === void 0)
           resumeSignal = null;
-        if (resumeSignal !== null)
+        if (resumeSignal != null)
           resumeSignal.then(this[_resume]);
         this[_pauseCount] = dart.notNull(this[_pauseCount]) + 1;
       }
       resume() {
         this[_resume](null);
       }
       [_resume](_) {
         if (dart.notNull(this[_pauseCount]) > 0)
           this[_pauseCount] = dart.notNull(this[_pauseCount]) - 1;
       }
@@ skipping 73 matching lines @@
         if (value === void 0)
           value = null;
         return new _Future.immediate(value);
       }
       error(error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         error = _nonNullError(error);
         if (!dart.notNull(core.identical(Zone.current, _ROOT_ZONE))) {
           let replacement = Zone.current.errorCallback(error, stackTrace);
-          if (replacement !== null) {
+          if (replacement != null) {
             error = _nonNullError(replacement.error);
             stackTrace = replacement.stackTrace;
           }
         }
         return new _Future.immediateError(error, stackTrace);
       }
       delayed(duration, computation) {
         if (computation === void 0)
           computation = null;
         let result = new _Future();
         new Timer(duration, (() => {
           try {
-            result._complete(computation === null ? null : computation());
+            result._complete(computation == null ? null : computation());
           } catch (e) {
             let s = dart.stackTrace(e);
             _completeWithErrorCallback(result, e, s);
           }
 
         }).bind(this));
         return dart.as(result, Future$(T));
       }
       static wait(futures, opts) {
         let eagerError = opts && 'eagerError' in opts ? opts.eagerError : false;
         let cleanUp = opts && 'cleanUp' in opts ? opts.cleanUp : null;
         let result = new _Future();
         let values = null;
         let remaining = 0;
         let error = null;
         let stackTrace = null;
         // Function handleError: (dynamic, dynamic) → void
         function handleError(theError, theStackTrace) {
           remaining = dart.notNull(remaining) - 1;
-          if (values !== null) {
-            if (cleanUp !== null) {
+          if (values != null) {
+            if (cleanUp != null) {
               for (let value of values) {
-                if (value !== null) {
+                if (value != null) {
                   new Future.sync(() => {
                     dart.dinvokef(cleanUp, value);
                   });
                 }
               }
             }
             values = null;
-            if (remaining === 0 || dart.notNull(eagerError)) {
+            if (remaining == 0 || dart.notNull(eagerError)) {
               result._completeError(theError, dart.as(theStackTrace, core.StackTrace));
             } else {
               error = theError;
               stackTrace = dart.as(theStackTrace, core.StackTrace);
             }
-          } else if (remaining === 0 && !dart.notNull(eagerError)) {
+          } else if (remaining == 0 && !dart.notNull(eagerError)) {
             result._completeError(error, stackTrace);
           }
         }
         for (let future of futures) {
           let pos = ((x) => remaining = dart.notNull(x) + 1, x)(remaining);
           future.then(((value) => {
             remaining = dart.notNull(remaining) - 1;
-            if (values !== null) {
+            if (values != null) {
               values.set(pos, value);
-              if (remaining === 0) {
+              if (remaining == 0) {
                 result._completeWithValue(values);
               }
             } else {
-              if (dart.notNull(cleanUp !== null) && dart.notNull(value !== null)) {
+              if (dart.notNull(cleanUp != null) && dart.notNull(value != null)) {
                 new Future.sync(() => {
                   dart.dinvokef(cleanUp, value);
                 });
               }
-              if (remaining === 0 && !dart.notNull(eagerError)) {
+              if (remaining == 0 && !dart.notNull(eagerError)) {
                 result._completeError(error, stackTrace);
               }
             }
           }).bind(this), {onError: handleError});
         }
-        if (remaining === 0) {
+        if (remaining == 0) {
           return dart.as(new Future.value(/* Unimplemented const */new core.List.from([])), Future$(core.List));
         }
         values = new core.List(remaining);
         return result;
       }
       static forEach(input, f) {
         let iterator = input.iterator;
         return Future.doWhile((() => {
           if (!dart.notNull(iterator.moveNext()))
             return false;
@@ skipping 29 matching lines @@
   let Future = Future$(dart.dynamic);
   class TimeoutException extends core.Object {
     TimeoutException(message, duration) {
       if (duration === void 0)
         duration = null;
       this.message = message;
       this.duration = duration;
     }
     toString() {
       let result = "TimeoutException";
-      if (this.duration !== null)
+      if (this.duration != null)
         result = `TimeoutException after ${this.duration}`;
-      if (this.message !== null)
+      if (this.message != null)
         result = `${result}: ${this.message}`;
       return result;
     }
   }
   let Completer$ = dart.generic(function(T) {
     class Completer extends core.Object {
       Completer() {
         return new _AsyncCompleter();
       }
       sync() {
         return new _SyncCompleter();
       }
     }
     dart.defineNamedConstructor(Completer, 'sync');
     return Completer;
   });
   let Completer = Completer$(dart.dynamic);
   // Function _completeWithErrorCallback: (_Future<dynamic>, dynamic, dynamic) → void
   function _completeWithErrorCallback(result, error, stackTrace) {
     let replacement = Zone.current.errorCallback(error, dart.as(stackTrace, core.StackTrace));
-    if (replacement !== null) {
+    if (replacement != null) {
       error = _nonNullError(replacement.error);
       stackTrace = replacement.stackTrace;
     }
     result._completeError(error, dart.as(stackTrace, core.StackTrace));
   }
   // Function _nonNullError: (Object) → Object
   function _nonNullError(error) {
-    return error !== null ? error : new core.NullThrownError();
+    return error != null ? error : new core.NullThrownError();
   }
   let _Completer$ = dart.generic(function(T) {
     class _Completer extends core.Object {
       _Completer() {
         this.future = new _Future();
       }
       completeError(error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         error = _nonNullError(error);
         if (!dart.notNull(this.future[_mayComplete]))
           throw new core.StateError("Future already completed");
         let replacement = Zone.current.errorCallback(error, stackTrace);
-        if (replacement !== null) {
+        if (replacement != null) {
           error = _nonNullError(replacement.error);
           stackTrace = replacement.stackTrace;
         }
         this[_completeError](error, stackTrace);
       }
       get isCompleted() {
         return !dart.notNull(this.future[_mayComplete]);
       }
     }
     return _Completer;
@@ skipping 33 matching lines @@
   let _SyncCompleter = _SyncCompleter$(dart.dynamic);
   let _nextListener = Symbol('_nextListener');
   let _onValue = Symbol('_onValue');
   let _errorTest = Symbol('_errorTest');
   let _whenCompleteAction = Symbol('_whenCompleteAction');
   class _FutureListener extends core.Object {
     then(result, onValue, errorCallback) {
       this.result = result;
       this.callback = onValue;
       this.errorCallback = errorCallback;
-      this.state = errorCallback === null ? _FutureListener.STATE_THEN : _FutureListener.STATE_THEN_ONERROR;
+      this.state = errorCallback == null ? _FutureListener.STATE_THEN : _FutureListener.STATE_THEN_ONERROR;
       this[_nextListener] = null;
     }
     catchError(result, errorCallback, test) {
       this.result = result;
       this.errorCallback = errorCallback;
       this.callback = test;
-      this.state = test === null ? _FutureListener.STATE_CATCHERROR : _FutureListener.STATE_CATCHERROR_TEST;
+      this.state = test == null ? _FutureListener.STATE_CATCHERROR : _FutureListener.STATE_CATCHERROR_TEST;
       this[_nextListener] = null;
     }
     whenComplete(result, onComplete) {
       this.result = result;
       this.callback = onComplete;
       this.errorCallback = null;
       this.state = _FutureListener.STATE_WHENCOMPLETE;
       this[_nextListener] = null;
     }
     chain(result) {
       this.result = result;
       this.callback = null;
       this.errorCallback = null;
       this.state = _FutureListener.STATE_CHAIN;
       this[_nextListener] = null;
     }
     get [_zone]() {
       return this.result[_zone];
     }
     get handlesValue() {
-      return (dart.notNull(this.state) & dart.notNull(_FutureListener.MASK_VALUE)) !== 0;
+      return (dart.notNull(this.state) & dart.notNull(_FutureListener.MASK_VALUE)) != 0;
     }
     get handlesError() {
-      return (dart.notNull(this.state) & dart.notNull(_FutureListener.MASK_ERROR)) !== 0;
+      return (dart.notNull(this.state) & dart.notNull(_FutureListener.MASK_ERROR)) != 0;
     }
     get hasErrorTest() {
-      return this.state === _FutureListener.STATE_CATCHERROR_TEST;
+      return this.state == _FutureListener.STATE_CATCHERROR_TEST;
     }
     get handlesComplete() {
-      return this.state === _FutureListener.STATE_WHENCOMPLETE;
+      return this.state == _FutureListener.STATE_WHENCOMPLETE;
     }
     get [_onValue]() {
       dart.assert(this.handlesValue);
       return dart.as(this.callback, _FutureOnValue);
     }
     get [_onError]() {
       return this.errorCallback;
     }
     get [_errorTest]() {
       dart.assert(this.hasErrorTest);
@@ skipping 56 matching lines @@
       }
       immediateError(error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         this[_zone] = Zone.current;
         this[_state] = _Future[_INCOMPLETE];
         this[_resultOrListeners] = null;
         this[_asyncCompleteError](error, stackTrace);
       }
       get [_mayComplete]() {
-        return this[_state] === _Future[_INCOMPLETE];
+        return this[_state] == _Future[_INCOMPLETE];
       }
       get [_isChained]() {
-        return this[_state] === _Future[_CHAINED];
+        return this[_state] == _Future[_CHAINED];
       }
       get [_isComplete]() {
         return dart.notNull(this[_state]) >= dart.notNull(_Future[_VALUE]);
       }
       get [_hasValue]() {
-        return this[_state] === _Future[_VALUE];
+        return this[_state] == _Future[_VALUE];
       }
       get [_hasError]() {
-        return this[_state] === _Future[_ERROR];
+        return this[_state] == _Future[_ERROR];
       }
       set [_isChained](value) {
         if (value) {
           dart.assert(!dart.notNull(this[_isComplete]));
           this[_state] = _Future[_CHAINED];
         } else {
           dart.assert(this[_isChained]);
           this[_state] = _Future[_INCOMPLETE];
         }
       }
       then(f, opts) {
         let onError = opts && 'onError' in opts ? opts.onError : null;
         let result = new _Future();
         if (!dart.notNull(core.identical(result[_zone], _ROOT_ZONE))) {
           f = dart.closureWrap(result[_zone].registerUnaryCallback(f), "(T) → dynamic");
-          if (onError !== null) {
+          if (onError != null) {
             onError = _registerErrorHandler(onError, result[_zone]);
           }
         }
         this[_addListener](new _FutureListener.then(result, f, onError));
         return result;
       }
       catchError(onError, opts) {
         let test = opts && 'test' in opts ? opts.test : null;
         let result = new _Future();
         if (!dart.notNull(core.identical(result[_zone], _ROOT_ZONE))) {
           onError = _registerErrorHandler(onError, result[_zone]);
-          if (test !== null)
+          if (test != null)
             test = dart.closureWrap(result[_zone].registerUnaryCallback(test), "(dynamic) → bool");
         }
         this[_addListener](new _FutureListener.catchError(result, onError, test));
         return result;
       }
       whenComplete(action) {
         let result = new _Future();
         if (!dart.notNull(core.identical(result[_zone], _ROOT_ZONE))) {
           action = result[_zone].registerCallback(action);
         }
@@ skipping 23 matching lines @@
       }
       [_setErrorObject](error) {
         dart.assert(!dart.notNull(this[_isComplete]));
         this[_state] = _Future[_ERROR];
         this[_resultOrListeners] = error;
       }
       [_setError](error, stackTrace) {
         this[_setErrorObject](new AsyncError(error, stackTrace));
       }
       [_addListener](listener) {
-        dart.assert(listener[_nextListener] === null);
+        dart.assert(listener[_nextListener] == null);
         if (this[_isComplete]) {
           this[_zone].scheduleMicrotask((() => {
             _Future[_propagateToListeners](this, listener);
           }).bind(this));
         } else {
           listener[_nextListener] = dart.as(this[_resultOrListeners], _FutureListener);
           this[_resultOrListeners] = listener;
         }
       }
       [_removeListeners]() {
         dart.assert(!dart.notNull(this[_isComplete]));
         let current = dart.as(this[_resultOrListeners], _FutureListener);
         this[_resultOrListeners] = null;
         let prev = null;
-        while (current !== null) {
+        while (current != null) {
           let next = current[_nextListener];
           current[_nextListener] = prev;
           prev = current;
           current = next;
         }
         return prev;
       }
       static [_chainForeignFuture](source, target) {
         dart.assert(!dart.notNull(target[_isComplete]));
         dart.assert(!dart.is(source, _Future));
@@ skipping 43 matching lines @@
       [_completeError](error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         dart.assert(!dart.notNull(this[_isComplete]));
         let listeners = this[_removeListeners]();
         this[_setError](error, stackTrace);
         _Future[_propagateToListeners](this, listeners);
       }
       [_asyncComplete](value) {
         dart.assert(!dart.notNull(this[_isComplete]));
-        if (value === null) {
+        if (value == null) {
         } else if (dart.is(value, Future)) {
           let typedFuture = dart.as(value, Future$(T));
           if (dart.is(typedFuture, _Future)) {
             let coreFuture = dart.as(typedFuture, _Future$(T));
             if (dart.notNull(coreFuture[_isComplete]) && dart.notNull(coreFuture[_hasError])) {
               this[_markPendingCompletion]();
               this[_zone].scheduleMicrotask((() => {
                 _Future[_chainCoreFuture](coreFuture, this);
               }).bind(this));
             } else {
@@ skipping 15 matching lines @@
         dart.assert(!dart.notNull(this[_isComplete]));
         this[_markPendingCompletion]();
         this[_zone].scheduleMicrotask((() => {
           this[_completeError](error, stackTrace);
         }).bind(this));
       }
       static [_propagateToListeners](source, listeners) {
         while (true) {
           dart.assert(source[_isComplete]);
           let hasError = source[_hasError];
-          if (listeners === null) {
+          if (listeners == null) {
             if (hasError) {
               let asyncError = source[_error];
               source[_zone].handleUncaughtError(asyncError.error, asyncError.stackTrace);
             }
             return;
           }
-          while (listeners[_nextListener] !== null) {
+          while (listeners[_nextListener] != null) {
             let listener = listeners;
             listeners = listener[_nextListener];
             listener[_nextListener] = null;
             _Future[_propagateToListeners](source, listener);
           }
           let listener = listeners;
           let listenerHasValue = true;
           let sourceValue = hasError ? null : source[_value];
           let listenerValueOrError = sourceValue;
           let isPropagationAborted = false;
@@ skipping 30 matching lines @@
                   matchesTest = dart.as(zone.runUnary(test, asyncError.error), core.bool);
                 } catch (e) {
                   let s = dart.stackTrace(e);
                   listenerValueOrError = core.identical(asyncError.error, e) ? asyncError : new AsyncError(e, s);
                   listenerHasValue = false;
                   return;
                 }
 
               }
               let errorCallback = listener[_onError];
-              if (dart.notNull(matchesTest) && dart.notNull(errorCallback !== null)) {
+              if (dart.notNull(matchesTest) && dart.notNull(errorCallback != null)) {
                 try {
                   if (dart.is(errorCallback, ZoneBinaryCallback)) {
                     listenerValueOrError = zone.runBinary(errorCallback, asyncError.error, asyncError.stackTrace);
                   } else {
                     listenerValueOrError = zone.runUnary(dart.as(errorCallback, dart.throw_("Unimplemented type (dynamic) → dynamic")), asyncError.error);
                   }
                 } catch (e) {
                   let s = dart.stackTrace(e);
                   listenerValueOrError = core.identical(asyncError.error, e) ? asyncError : new AsyncError(e, s);
                   listenerHasValue = false;
@@ skipping 44 matching lines @@
             if (!dart.notNull(hasError)) {
               if (listener.handlesValue) {
                 listenerHasValue = handleValueCallback();
               }
             } else {
               handleError();
             }
             if (listener.handlesComplete) {
               handleWhenCompleteCallback();
             }
-            if (oldZone !== null)
+            if (oldZone != null)
               Zone._leave(oldZone);
             if (isPropagationAborted)
               return;
             if (dart.notNull(listenerHasValue) && !dart.notNull(core.identical(sourceValue, listenerValueOrError)) && dart.notNull(dart.is(listenerValueOrError, Future))) {
               let chainSource = dart.as(listenerValueOrError, Future);
               let result = listener.result;
               if (dart.is(chainSource, _Future)) {
                 if (chainSource[_isComplete]) {
                   result[_isChained] = true;
                   source = chainSource;
@@ skipping 18 matching lines @@
           }
           source = result;
         }
       }
       timeout(timeLimit, opts) {
         let onTimeout = opts && 'onTimeout' in opts ? opts.onTimeout : null;
         if (this[_isComplete])
           return new _Future.immediate(this);
         let result = new _Future();
         let timer = null;
-        if (onTimeout === null) {
+        if (onTimeout == null) {
           timer = new Timer(timeLimit, (() => {
             result._completeError(new TimeoutException("Future not completed", timeLimit));
           }).bind(this));
         } else {
           let zone = Zone.current;
           onTimeout = zone.registerCallback(onTimeout);
           timer = new Timer(timeLimit, (() => {
             try {
               result._complete(zone.run(onTimeout));
             } catch (e) {
@@ skipping 32 matching lines @@
       this.callback = callback;
       this.next = null;
     }
   }
   exports._nextCallback = null;
   exports._lastCallback = null;
   exports._lastPriorityCallback = null;
   exports._isInCallbackLoop = false;
   // Function _asyncRunCallbackLoop: () → void
   function _asyncRunCallbackLoop() {
-    while (exports._nextCallback !== null) {
+    while (exports._nextCallback != null) {
       exports._lastPriorityCallback = null;
       let entry = exports._nextCallback;
       exports._nextCallback = entry.next;
-      if (exports._nextCallback === null)
+      if (exports._nextCallback == null)
         exports._lastCallback = null;
       entry.callback();
     }
   }
   // Function _asyncRunCallback: () → void
   function _asyncRunCallback() {
     exports._isInCallbackLoop = true;
     try {
       _asyncRunCallbackLoop();
     } finally {
       exports._lastPriorityCallback = null;
       exports._isInCallbackLoop = false;
-      if (exports._nextCallback !== null)
+      if (exports._nextCallback != null)
         _AsyncRun._scheduleImmediate(_asyncRunCallback);
     }
   }
   // Function _scheduleAsyncCallback: (dynamic) → void
   function _scheduleAsyncCallback(callback) {
-    if (exports._nextCallback === null) {
+    if (exports._nextCallback == null) {
       exports._nextCallback = exports._lastCallback = new _AsyncCallbackEntry(dart.as(callback, _AsyncCallback));
       if (!dart.notNull(exports._isInCallbackLoop)) {
         _AsyncRun._scheduleImmediate(_asyncRunCallback);
       }
     } else {
       let newEntry = new _AsyncCallbackEntry(dart.as(callback, _AsyncCallback));
       exports._lastCallback.next = newEntry;
       exports._lastCallback = newEntry;
     }
   }
   // Function _schedulePriorityAsyncCallback: (dynamic) → void
   function _schedulePriorityAsyncCallback(callback) {
     let entry = new _AsyncCallbackEntry(dart.as(callback, _AsyncCallback));
-    if (exports._nextCallback === null) {
+    if (exports._nextCallback == null) {
       _scheduleAsyncCallback(callback);
       exports._lastPriorityCallback = exports._lastCallback;
-    } else if (exports._lastPriorityCallback === null) {
+    } else if (exports._lastPriorityCallback == null) {
       entry.next = exports._nextCallback;
       exports._nextCallback = exports._lastPriorityCallback = entry;
     } else {
       entry.next = exports._lastPriorityCallback.next;
       exports._lastPriorityCallback.next = entry;
       exports._lastPriorityCallback = entry;
-      if (entry.next === null) {
+      if (entry.next == null) {
         exports._lastCallback = entry;
       }
     }
   }
   // Function scheduleMicrotask: (() → void) → void
   function scheduleMicrotask(callback) {
     if (core.identical(_ROOT_ZONE, Zone.current)) {
       _rootScheduleMicrotask(null, null, _ROOT_ZONE, callback);
       return;
     }
     Zone.current.scheduleMicrotask(Zone.current.bindCallback(callback, {runGuarded: true}));
   }
   let _scheduleImmediate = Symbol('_scheduleImmediate');
   let _initializeScheduleImmediate = Symbol('_initializeScheduleImmediate');
   let _scheduleImmediateJsOverride = Symbol('_scheduleImmediateJsOverride');
   let _scheduleImmediateWithSetImmediate = Symbol('_scheduleImmediateWithSetImmediate');
   let _scheduleImmediateWithTimer = Symbol('_scheduleImmediateWithTimer');
   class _AsyncRun extends core.Object {
     static [_scheduleImmediate](callback) {
       dart.dinvokef(_AsyncRun.scheduleImmediateClosure, callback);
     }
     static [_initializeScheduleImmediate]() {
       _js_helper.requiresPreamble();
-      if (self.scheduleImmediate !== null) {
+      if (self.scheduleImmediate != null) {
         return _AsyncRun[_scheduleImmediateJsOverride];
       }
-      if (dart.notNull(self.MutationObserver !== null) && dart.notNull(self.document !== null)) {
+      if (dart.notNull(self.MutationObserver != null) && dart.notNull(self.document != null)) {
         let div = self.document.createElement("div");
         let span = self.document.createElement("span");
         let storedCallback = null;
         // Function internalCallback: (dynamic) → dynamic
         function internalCallback(_) {
           _isolate_helper.leaveJsAsync();
           let f = storedCallback;
           storedCallback = null;
           dart.dinvokef(f);
         }
         ;
         let observer = new self.MutationObserver(_js_helper.convertDartClosureToJS(internalCallback, 1));
         observer.observe(div, {childList: true});
         return (callback) => {
-          dart.assert(storedCallback === null);
+          dart.assert(storedCallback == null);
           _isolate_helper.enterJsAsync();
           storedCallback = callback;
           div.firstChild ? div.removeChild(span) : div.appendChild(span);
         };
-      } else if (self.setImmediate !== null) {
+      } else if (self.setImmediate != null) {
         return _AsyncRun[_scheduleImmediateWithSetImmediate];
       }
       return _AsyncRun[_scheduleImmediateWithTimer];
     }
     static [_scheduleImmediateJsOverride](callback) {
       // Function internalCallback: () → dynamic
       function internalCallback() {
         _isolate_helper.leaveJsAsync();
         callback();
       }
@@ skipping 112 matching lines @@
   });
   let _ControllerEventSinkWrapper = _ControllerEventSinkWrapper$(dart.dynamic);
   let StreamController$ = dart.generic(function(T) {
     class StreamController extends core.Object {
       StreamController(opts) {
         let onListen = opts && 'onListen' in opts ? opts.onListen : null;
         let onPause = opts && 'onPause' in opts ? opts.onPause : null;
         let onResume = opts && 'onResume' in opts ? opts.onResume : null;
         let onCancel = opts && 'onCancel' in opts ? opts.onCancel : null;
         let sync = opts && 'sync' in opts ? opts.sync : false;
-        if (dart.notNull(onListen === null) && dart.notNull(onPause === null) && dart.notNull(onResume === null) && dart.notNull(onCancel === null)) {
+        if (dart.notNull(onListen == null) && dart.notNull(onPause == null) && dart.notNull(onResume == null) && dart.notNull(onCancel == null)) {
           return dart.as(sync ? new _NoCallbackSyncStreamController() : new _NoCallbackAsyncStreamController(), StreamController$(T));
         }
         return sync ? new _SyncStreamController(onListen, onPause, onResume, onCancel) : new _AsyncStreamController(onListen, onPause, onResume, onCancel);
       }
       broadcast(opts) {
         let onListen = opts && 'onListen' in opts ? opts.onListen : null;
         let onCancel = opts && 'onCancel' in opts ? opts.onCancel : null;
         let sync = opts && 'sync' in opts ? opts.sync : false;
         return sync ? new _SyncBroadcastStreamController(onListen, onCancel) : new _AsyncBroadcastStreamController(onListen, onCancel);
       }
@@ skipping 30 matching lines @@
         this[_state] = _StreamController[_STATE_INITIAL];
         this[_doneFuture] = null;
       }
       get stream() {
         return dart.as(new _ControllerStream(this), Stream$(T));
       }
       get sink() {
         return new _StreamSinkWrapper(this);
       }
       get [_isCanceled]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_CANCELED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_CANCELED])) != 0;
       }
       get hasListener() {
-        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_SUBSCRIBED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_SUBSCRIBED])) != 0;
       }
       get [_isInitialState]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_SUBSCRIPTION_MASK])) === _StreamController[_STATE_INITIAL];
+        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_SUBSCRIPTION_MASK])) == _StreamController[_STATE_INITIAL];
       }
       get isClosed() {
-        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_CLOSED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_CLOSED])) != 0;
       }
       get isPaused() {
         return this.hasListener ? this[_subscription][_isInputPaused] : !dart.notNull(this[_isCanceled]);
       }
       get [_isAddingStream]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_ADDSTREAM])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_StreamController[_STATE_ADDSTREAM])) != 0;
       }
       get [_mayAddEvent]() {
         return dart.notNull(this[_state]) < dart.notNull(_StreamController[_STATE_CLOSED]);
       }
       get [_pendingEvents]() {
         dart.assert(this[_isInitialState]);
         if (!dart.notNull(this[_isAddingStream])) {
           return dart.as(this[_varData], _PendingEvents);
         }
         let state = dart.as(this[_varData], _StreamControllerAddStreamState);
         return dart.as(state.varData, _PendingEvents);
       }
       [_ensurePendingEvents]() {
         dart.assert(this[_isInitialState]);
         if (!dart.notNull(this[_isAddingStream])) {
-          if (this[_varData] === null)
+          if (this[_varData] == null)
             this[_varData] = new _StreamImplEvents();
           return dart.as(this[_varData], _StreamImplEvents);
         }
         let state = dart.as(this[_varData], _StreamControllerAddStreamState);
-        if (state.varData === null)
+        if (state.varData == null)
           state.varData = new _StreamImplEvents();
         return dart.as(state.varData, _StreamImplEvents);
       }
       get [_subscription]() {
         dart.assert(this.hasListener);
         if (this[_isAddingStream]) {
           let addState = dart.as(this[_varData], _StreamControllerAddStreamState);
           return dart.as(addState.varData, _ControllerSubscription);
         }
         return dart.as(this[_varData], _ControllerSubscription);
@@ skipping 13 matching lines @@
           return new _Future.immediate(null);
         let addState = new _StreamControllerAddStreamState(this, this[_varData], source, cancelOnError);
         this[_varData] = addState;
         this[_state] = _StreamController[_STATE_ADDSTREAM];
         return addState.addStreamFuture;
       }
       get done() {
         return this[_ensureDoneFuture]();
       }
       [_ensureDoneFuture]() {
-        if (this[_doneFuture] === null) {
+        if (this[_doneFuture] == null) {
           this[_doneFuture] = this[_isCanceled] ? Future[_nullFuture] : new _Future();
         }
         return this[_doneFuture];
       }
       add(value) {
         if (!dart.notNull(this[_mayAddEvent]))
           throw this[_badEventState]();
         this[_add](value);
       }
       addError(error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
         error = _nonNullError(error);
         if (!dart.notNull(this[_mayAddEvent]))
           throw this[_badEventState]();
         let replacement = Zone.current.errorCallback(error, stackTrace);
-        if (replacement !== null) {
+        if (replacement != null) {
           error = _nonNullError(replacement.error);
           stackTrace = replacement.stackTrace;
         }
         this[_addError](error, stackTrace);
       }
       close() {
         if (this.isClosed) {
           return this[_ensureDoneFuture]();
         }
         if (!dart.notNull(this[_mayAddEvent]))
@@ skipping 51 matching lines @@
         return dart.as(subscription, StreamSubscription$(T));
       }
       [_recordCancel](subscription) {
         let result = null;
         if (this[_isAddingStream]) {
           let addState = dart.as(this[_varData], _StreamControllerAddStreamState);
           result = addState.cancel();
         }
         this[_varData] = null;
         this[_state] = dart.notNull(this[_state]) & ~(dart.notNull(_StreamController[_STATE_SUBSCRIBED]) | dart.notNull(_StreamController[_STATE_ADDSTREAM])) | dart.notNull(_StreamController[_STATE_CANCELED]);
-        if (this[_onCancel] !== null) {
-          if (result === null) {
+        if (this[_onCancel] != null) {
+          if (result == null) {
             try {
               result = dart.as(this[_onCancel](), Future);
             } catch (e) {
               let s = dart.stackTrace(e);
               result = ((_$) => {
                 _$._asyncCompleteError(e, s);
                 return _$;
               }).bind(this)(new _Future());
             }
 
           } else {
             result = result.whenComplete(this[_onCancel]);
           }
         }
         // Function complete: () → void
         function complete() {
-          if (dart.notNull(this[_doneFuture] !== null) && dart.notNull(this[_doneFuture][_mayComplete])) {
+          if (dart.notNull(this[_doneFuture] != null) && dart.notNull(this[_doneFuture][_mayComplete])) {
             this[_doneFuture]._asyncComplete(null);
           }
         }
-        if (result !== null) {
+        if (result != null) {
           result = result.whenComplete(complete);
         } else {
           complete();
         }
         return result;
       }
       [_recordPause](subscription) {
         if (this[_isAddingStream]) {
           let addState = dart.as(this[_varData], _StreamControllerAddStreamState);
           addState.pause();
@@ skipping 86 matching lines @@
     get [_onCancel]() {
       return null;
     }
   }
   class _NoCallbackAsyncStreamController extends dart.mixin(_AsyncStreamControllerDispatch, _NoCallbacks) {
   }
   class _NoCallbackSyncStreamController extends dart.mixin(_SyncStreamControllerDispatch, _NoCallbacks) {
   }
   // Function _runGuarded: (() → dynamic) → Future<dynamic>
   function _runGuarded(notificationHandler) {
-    if (notificationHandler === null)
+    if (notificationHandler == null)
       return null;
     try {
       let result = notificationHandler();
       if (dart.is(result, Future))
         return dart.as(result, Future);
       return null;
     } catch (e) {
       let s = dart.stackTrace(e);
       Zone.current.handleUncaughtError(e, s);
     }
@@ skipping 40 matching lines @@
         }).bind(this);
       }
       pause() {
         this.addSubscription.pause();
       }
       resume() {
         this.addSubscription.resume();
       }
       cancel() {
         let cancel = this.addSubscription.cancel();
-        if (cancel === null) {
+        if (cancel == null) {
           this.addStreamFuture._asyncComplete(null);
           return null;
         }
         return cancel.whenComplete((() => {
           this.addStreamFuture._asyncComplete(null);
         }).bind(this));
       }
       complete() {
         this.addStreamFuture._asyncComplete(null);
       }
@@ skipping 49 matching lines @@
   let _GeneratedStreamImpl = _GeneratedStreamImpl$(dart.dynamic);
   let _iterator = Symbol('_iterator');
   let _STATE_UNSCHEDULED = Symbol('_STATE_UNSCHEDULED');
   let _STATE_SCHEDULED = Symbol('_STATE_SCHEDULED');
   let _eventScheduled = Symbol('_eventScheduled');
   class _PendingEvents extends core.Object {
     _PendingEvents() {
       this[_state] = _PendingEvents[_STATE_UNSCHEDULED];
     }
     get isScheduled() {
-      return this[_state] === _PendingEvents[_STATE_SCHEDULED];
+      return this[_state] == _PendingEvents[_STATE_SCHEDULED];
     }
     get [_eventScheduled]() {
       return dart.notNull(this[_state]) >= dart.notNull(_PendingEvents[_STATE_SCHEDULED]);
     }
     schedule(dispatch) {
       if (this.isScheduled)
         return;
       dart.assert(!dart.notNull(this.isEmpty));
       if (this[_eventScheduled]) {
-        dart.assert(this[_state] === _PendingEvents[_STATE_CANCELED]);
+        dart.assert(this[_state] == _PendingEvents[_STATE_CANCELED]);
         this[_state] = _PendingEvents[_STATE_SCHEDULED];
         return;
       }
       scheduleMicrotask((() => {
         let oldState = this[_state];
         this[_state] = _PendingEvents[_STATE_UNSCHEDULED];
-        if (oldState === _PendingEvents[_STATE_CANCELED])
+        if (oldState == _PendingEvents[_STATE_CANCELED])
           return;
         this.handleNext(dispatch);
       }).bind(this));
       this[_state] = _PendingEvents[_STATE_SCHEDULED];
     }
     cancelSchedule() {
       if (this.isScheduled)
         this[_state] = _PendingEvents[_STATE_CANCELED];
     }
   }
   _PendingEvents._STATE_UNSCHEDULED = 0;
   _PendingEvents._STATE_SCHEDULED = 1;
   _PendingEvents._STATE_CANCELED = 3;
   let _IterablePendingEvents$ = dart.generic(function(T) {
     class _IterablePendingEvents extends _PendingEvents {
       _IterablePendingEvents(data) {
         this[_iterator] = data.iterator;
         super._PendingEvents();
       }
       get isEmpty() {
-        return this[_iterator] === null;
+        return this[_iterator] == null;
       }
       handleNext(dispatch) {
-        if (this[_iterator] === null) {
+        if (this[_iterator] == null) {
           throw new core.StateError("No events pending.");
         }
         let isDone = null;
         try {
           isDone = !dart.notNull(this[_iterator].moveNext());
         } catch (e) {
           let s = dart.stackTrace(e);
           this[_iterator] = null;
           dispatch._sendError(e, s);
           return;
@@ skipping 68 matching lines @@
       throw new core.StateError("No events after a done.");
     }
   }
   class _StreamImplEvents extends _PendingEvents {
     _StreamImplEvents() {
       this.firstPendingEvent = null;
       this.lastPendingEvent = null;
       super._PendingEvents();
     }
     get isEmpty() {
-      return this.lastPendingEvent === null;
+      return this.lastPendingEvent == null;
     }
     add(event) {
-      if (this.lastPendingEvent === null) {
+      if (this.lastPendingEvent == null) {
         this.firstPendingEvent = this.lastPendingEvent = event;
       } else {
         this.lastPendingEvent = this.lastPendingEvent.next = event;
       }
     }
     handleNext(dispatch) {
       dart.assert(!dart.notNull(this.isScheduled));
       let event = this.firstPendingEvent;
       this.firstPendingEvent = event.next;
-      if (this.firstPendingEvent === null) {
+      if (this.firstPendingEvent == null) {
         this.lastPendingEvent = null;
       }
       event.perform(dispatch);
     }
     clear() {
       if (this.isScheduled)
         this.cancelSchedule();
       this.firstPendingEvent = this.lastPendingEvent = null;
     }
   }
@@ skipping 25 matching lines @@
   let _PAUSED = Symbol('_PAUSED');
   let _DoneStreamSubscription$ = dart.generic(function(T) {
     class _DoneStreamSubscription extends core.Object {
       _DoneStreamSubscription(onDone$) {
         this[_onDone] = onDone$;
         this[_zone] = Zone.current;
         this[_state] = 0;
         this[_schedule]();
       }
       get [_isSent]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_DoneStreamSubscription[_DONE_SENT])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_DoneStreamSubscription[_DONE_SENT])) != 0;
       }
       get [_isScheduled]() {
-        return (dart.notNull(this[_state]) & dart.notNull(_DoneStreamSubscription[_SCHEDULED])) !== 0;
+        return (dart.notNull(this[_state]) & dart.notNull(_DoneStreamSubscription[_SCHEDULED])) != 0;
       }
       get isPaused() {
         return dart.notNull(this[_state]) >= dart.notNull(_DoneStreamSubscription[_PAUSED]);
       }
       [_schedule]() {
         if (this[_isScheduled])
           return;
         this[_zone].scheduleMicrotask(this[_sendDone]);
         this[_state] = _DoneStreamSubscription[_SCHEDULED];
       }
       onData(handleData) {}
       onError(handleError) {}
       onDone(handleDone) {
         this[_onDone] = handleDone;
       }
       pause(resumeSignal) {
         if (resumeSignal === void 0)
           resumeSignal = null;
         this[_state] = _DoneStreamSubscription[_PAUSED];
-        if (resumeSignal !== null)
+        if (resumeSignal != null)
           resumeSignal.whenComplete(this.resume);
       }
       resume() {
         if (this.isPaused) {
           this[_state] = _DoneStreamSubscription[_PAUSED];
           if (!dart.notNull(this.isPaused) && !dart.notNull(this[_isSent])) {
             this[_schedule]();
           }
         }
       }
       cancel() {
         return null;
       }
       asFuture(futureValue) {
         if (futureValue === void 0)
           futureValue = null;
         let result = new _Future();
         this[_onDone] = (() => {
           result._completeWithValue(null);
         }).bind(this);
         return result;
       }
       [_sendDone]() {
         this[_state] = ~dart.notNull(_DoneStreamSubscription[_SCHEDULED]);
         if (this.isPaused)
           return;
         this[_state] = _DoneStreamSubscription[_DONE_SENT];
-        if (this[_onDone] !== null)
+        if (this[_onDone] != null)
           this[_zone].runGuarded(this[_onDone]);
       }
     }
     _DoneStreamSubscription._DONE_SENT = 1;
     _DoneStreamSubscription._SCHEDULED = 2;
     _DoneStreamSubscription._PAUSED = 4;
     return _DoneStreamSubscription;
   });
   let _DoneStreamSubscription = _DoneStreamSubscription$(dart.dynamic);
   let _source = Symbol('_source');
@@ skipping 15 matching lines @@
         super.Stream();
         this[_controller] = new _AsBroadcastStreamController(this[_onListen], this[_onCancel]);
       }
       get isBroadcast() {
         return true;
       }
       listen(onData, opts) {
         let onError = opts && 'onError' in opts ? opts.onError : null;
         let onDone = opts && 'onDone' in opts ? opts.onDone : null;
         let cancelOnError = opts && 'cancelOnError' in opts ? opts.cancelOnError : null;
-        if (dart.notNull(this[_controller] === null) || dart.notNull(this[_controller].isClosed)) {
+        if (dart.notNull(this[_controller] == null) || dart.notNull(this[_controller].isClosed)) {
           return new _DoneStreamSubscription(onDone);
         }
-        if (this[_subscription] === null) {
+        if (this[_subscription] == null) {
           this[_subscription] = this[_source].listen(this[_controller].add, {onError: this[_controller].addError, onDone: this[_controller].close});
         }
         cancelOnError = core.identical(true, cancelOnError);
         return this[_controller]._subscribe(onData, onError, onDone, cancelOnError);
       }
       [_onCancel]() {
-        let shutdown = dart.notNull(this[_controller] === null) || dart.notNull(this[_controller].isClosed);
-        if (this[_onCancelHandler] !== null) {
+        let shutdown = dart.notNull(this[_controller] == null) || dart.notNull(this[_controller].isClosed);
+        if (this[_onCancelHandler] != null) {
           this[_zone].runUnary(this[_onCancelHandler], new _BroadcastSubscriptionWrapper(this));
         }
         if (shutdown) {
-          if (this[_subscription] !== null) {
+          if (this[_subscription] != null) {
             this[_subscription].cancel();
             this[_subscription] = null;
           }
         }
       }
       [_onListen]() {
-        if (this[_onListenHandler] !== null) {
+        if (this[_onListenHandler] != null) {
           this[_zone].runUnary(this[_onListenHandler], new _BroadcastSubscriptionWrapper(this));
         }
       }
       [_cancelSubscription]() {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return;
         let subscription = this[_subscription];
         this[_subscription] = null;
         this[_controller] = null;
         subscription.cancel();
       }
       [_pauseSubscription](resumeSignal) {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return;
         this[_subscription].pause(resumeSignal);
       }
       [_resumeSubscription]() {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return;
         this[_subscription].resume();
       }
       get [_isSubscriptionPaused]() {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return false;
         return this[_subscription].isPaused;
       }
     }
     return _AsBroadcastStream;
   });
   let _AsBroadcastStream = _AsBroadcastStream$(dart.dynamic);
   let _BroadcastSubscriptionWrapper$ = dart.generic(function(T) {
     class _BroadcastSubscriptionWrapper extends core.Object {
       _BroadcastSubscriptionWrapper(stream$) {
@@ skipping 47 matching lines @@
         this[_subscription] = null;
         this[_current] = null;
         this[_futureOrPrefetch] = null;
         this[_state] = _StreamIteratorImpl[_STATE_FOUND];
         this[_subscription] = stream.listen(this[_onData], {onError: this[_onError], onDone: this[_onDone], cancelOnError: true});
       }
       get current() {
         return this[_current];
       }
       moveNext() {
-        if (this[_state] === _StreamIteratorImpl[_STATE_DONE]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_DONE]) {
           return new _Future.immediate(false);
         }
-        if (this[_state] === _StreamIteratorImpl[_STATE_MOVING]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_MOVING]) {
           throw new core.StateError("Already waiting for next.");
         }
-        if (this[_state] === _StreamIteratorImpl[_STATE_FOUND]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_FOUND]) {
           this[_state] = _StreamIteratorImpl[_STATE_MOVING];
           this[_current] = null;
           this[_futureOrPrefetch] = new _Future();
           return dart.as(this[_futureOrPrefetch], Future$(core.bool));
         } else {
           dart.assert(dart.notNull(this[_state]) >= dart.notNull(_StreamIteratorImpl[_STATE_EXTRA_DATA]));
           switch (this[_state]) {
             case _StreamIteratorImpl[_STATE_EXTRA_DATA]:
             {
               this[_state] = _StreamIteratorImpl[_STATE_FOUND];
@@ skipping 17 matching lines @@
         }
       }
       [_clear]() {
         this[_subscription] = null;
         this[_futureOrPrefetch] = null;
         this[_current] = null;
         this[_state] = _StreamIteratorImpl[_STATE_DONE];
       }
       cancel() {
         let subscription = this[_subscription];
-        if (this[_state] === _StreamIteratorImpl[_STATE_MOVING]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_MOVING]) {
           let hasNext = dart.as(this[_futureOrPrefetch], _Future$(core.bool));
           this[_clear]();
           hasNext._complete(false);
         } else {
           this[_clear]();
         }
         return subscription.cancel();
       }
       [_onData](data) {
-        if (this[_state] === _StreamIteratorImpl[_STATE_MOVING]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_MOVING]) {
           this[_current] = data;
           let hasNext = dart.as(this[_futureOrPrefetch], _Future$(core.bool));
           this[_futureOrPrefetch] = null;
           this[_state] = _StreamIteratorImpl[_STATE_FOUND];
           hasNext._complete(true);
           return;
         }
         this[_subscription].pause();
-        dart.assert(this[_futureOrPrefetch] === null);
+        dart.assert(this[_futureOrPrefetch] == null);
         this[_futureOrPrefetch] = data;
         this[_state] = _StreamIteratorImpl[_STATE_EXTRA_DATA];
       }
       [_onError](error, stackTrace) {
         if (stackTrace === void 0)
           stackTrace = null;
-        if (this[_state] === _StreamIteratorImpl[_STATE_MOVING]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_MOVING]) {
           let hasNext = dart.as(this[_futureOrPrefetch], _Future$(core.bool));
           this[_clear]();
           hasNext._completeError(error, stackTrace);
           return;
         }
         this[_subscription].pause();
-        dart.assert(this[_futureOrPrefetch] === null);
+        dart.assert(this[_futureOrPrefetch] == null);
         this[_futureOrPrefetch] = new AsyncError(error, stackTrace);
         this[_state] = _StreamIteratorImpl[_STATE_EXTRA_ERROR];
       }
       [_onDone]() {
-        if (this[_state] === _StreamIteratorImpl[_STATE_MOVING]) {
+        if (this[_state] == _StreamIteratorImpl[_STATE_MOVING]) {
           let hasNext = dart.as(this[_futureOrPrefetch], _Future$(core.bool));
           this[_clear]();
           hasNext._complete(false);
           return;
         }
         this[_subscription].pause();
         this[_futureOrPrefetch] = null;
         this[_state] = _StreamIteratorImpl[_STATE_EXTRA_DONE];
       }
     }
     _StreamIteratorImpl._STATE_FOUND = 0;
     _StreamIteratorImpl._STATE_DONE = 1;
     _StreamIteratorImpl._STATE_MOVING = 2;
     _StreamIteratorImpl._STATE_EXTRA_DATA = 3;
     _StreamIteratorImpl._STATE_EXTRA_ERROR = 4;
     _StreamIteratorImpl._STATE_EXTRA_DONE = 5;
     return _StreamIteratorImpl;
   });
   let _StreamIteratorImpl = _StreamIteratorImpl$(dart.dynamic);
   // Function _runUserCode: (() → dynamic, (dynamic) → dynamic, (dynamic, StackTrace) → dynamic) → dynamic
   function _runUserCode(userCode, onSuccess, onError) {
     try {
       dart.dinvokef(onSuccess, userCode());
     } catch (e) {
       let s = dart.stackTrace(e);
       let replacement = Zone.current.errorCallback(e, s);
-      if (replacement === null) {
+      if (replacement == null) {
         dart.dinvokef(onError, e, s);
       } else {
         let error = _nonNullError(replacement.error);
         let stackTrace = replacement.stackTrace;
         dart.dinvokef(onError, error, stackTrace);
       }
     }
 
   }
   // Function _cancelAndError: (StreamSubscription<dynamic>, _Future<dynamic>, dynamic, StackTrace) → void
   function _cancelAndError(subscription, future, error, stackTrace) {
     let cancelFuture = subscription.cancel();
     if (dart.is(cancelFuture, Future)) {
       cancelFuture.whenComplete(() => future._completeError(error, stackTrace));
     } else {
       future._completeError(error, stackTrace);
     }
   }
   // Function _cancelAndErrorWithReplacement: (StreamSubscription<dynamic>, _Future<dynamic>, dynamic, StackTrace) → void
   function _cancelAndErrorWithReplacement(subscription, future, error, stackTrace) {
     let replacement = Zone.current.errorCallback(error, stackTrace);
-    if (replacement !== null) {
+    if (replacement != null) {
       error = _nonNullError(replacement.error);
       stackTrace = replacement.stackTrace;
     }
     _cancelAndError(subscription, future, error, stackTrace);
   }
   // Function _cancelAndErrorClosure: (StreamSubscription<dynamic>, _Future<dynamic>) → dynamic
   function _cancelAndErrorClosure(subscription, future) {
     return (error, stackTrace) => _cancelAndError(subscription, future, error, stackTrace);
   }
   // Function _cancelAndValue: (StreamSubscription<dynamic>, _Future<dynamic>, dynamic) → void
@@ skipping 53 matching lines @@
         if (this[_isClosed])
           return;
         super._add(data);
       }
       [_addError](error, stackTrace) {
         if (this[_isClosed])
           return;
         super._addError(error, stackTrace);
       }
       [_onPause]() {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return;
         this[_subscription].pause();
       }
       [_onResume]() {
-        if (this[_subscription] === null)
+        if (this[_subscription] == null)
           return;
         this[_subscription].resume();
       }
       [_onCancel]() {
-        if (this[_subscription] !== null) {
+        if (this[_subscription] != null) {
           let subscription = this[_subscription];
           this[_subscription] = null;
           subscription.cancel();
         }
         return null;
       }
       [_handleData](data) {
         this[_stream]._handleData(data, this);
       }
       [_handleError](error, stackTrace) {
         this[_stream]._handleError(error, stackTrace, this);
       }
       [_handleDone]() {
         this[_stream]._handleDone(this);
       }
     }
     return _ForwardingStreamSubscription;
   });
   let _ForwardingStreamSubscription = _ForwardingStreamSubscription$(dart.dynamic, dart.dynamic);
   // Function _addErrorWithReplacement: (_EventSink<dynamic>, dynamic, dynamic) → void
   function _addErrorWithReplacement(sink, error, stackTrace) {
     let replacement = Zone.current.errorCallback(error, dart.as(stackTrace, core.StackTrace));
-    if (replacement !== null) {
+    if (replacement != null) {
       error = _nonNullError(replacement.error);
       stackTrace = replacement.stackTrace;
     }
     sink._addError(error, dart.as(stackTrace, core.StackTrace));
   }
   let _test = Symbol('_test');
   let _WhereStream$ = dart.generic(function(T) {
     class _WhereStream extends _ForwardingStream$(T, T) {
       _WhereStream(source, test) {
         this[_test] = test;
@@ skipping 64 matching lines @@
   let _ExpandStream = _ExpandStream$(dart.dynamic, dart.dynamic);
   let _HandleErrorStream$ = dart.generic(function(T) {
     class _HandleErrorStream extends _ForwardingStream$(T, T) {
       _HandleErrorStream(source, onError, test) {
         this[_transform] = onError;
         this[_test] = test;
         super._ForwardingStream(source);
       }
       [_handleError](error, stackTrace, sink) {
         let matches = true;
-        if (this[_test] !== null) {
+        if (this[_test] != null) {
           try {
             matches = dart.dinvokef(this[_test], error);
           } catch (e) {
             let s = dart.stackTrace(e);
             _addErrorWithReplacement(sink, e, s);
             return;
           }
 
         }
         if (matches) {
@@ skipping 23 matching lines @@
       _TakeStream(source, count) {
         this[_remaining] = count;
         super._ForwardingStream(source);
         if (!(typeof count == 'number'))
           throw new core.ArgumentError(count);
       }
       [_handleData](inputEvent, sink) {
         if (dart.notNull(this[_remaining]) > 0) {
           sink._add(inputEvent);
           this[_remaining] = 1;
-          if (this[_remaining] === 0) {
+          if (this[_remaining] == 0) {
             sink._close();
           }
         }
       }
     }
     return _TakeStream;
   });
   let _TakeStream = _TakeStream$(dart.dynamic);
   let _TakeWhileStream$ = dart.generic(function(T) {
     class _TakeWhileStream extends _ForwardingStream$(T, T) {
@@ skipping 82 matching lines @@
         this[_equals] = equals;
         super._ForwardingStream(source);
       }
       [_handleData](inputEvent, sink) {
         if (core.identical(this[_previous], _DistinctStream[_SENTINEL])) {
           this[_previous] = inputEvent;
           return sink._add(inputEvent);
         } else {
           let isEqual = null;
           try {
-            if (this[_equals] === null) {
+            if (this[_equals] == null) {
               isEqual = dart.equals(this[_previous], inputEvent);
             } else {
               isEqual = this[_equals](dart.as(this[_previous], T), inputEvent);
             }
           } catch (e) {
             let s = dart.stackTrace(e);
             _addErrorWithReplacement(sink, e, s);
             return null;
           }
 
@@ skipping 39 matching lines @@
     class _SinkTransformerStreamSubscription extends _BufferingStreamSubscription$(T) {
       _SinkTransformerStreamSubscription(source, mapper, onData, onError, onDone, cancelOnError) {
         this[_transformerSink] = null;
         this[_subscription] = null;
         super._BufferingStreamSubscription(onData, onError, onDone, cancelOnError);
         let eventSink = new _EventSinkWrapper(this);
         this[_transformerSink] = mapper(eventSink);
         this[_subscription] = source.listen(this[_handleData], {onError: this[_handleError], onDone: this[_handleDone]});
       }
       get [_isSubscribed]() {
-        return this[_subscription] !== null;
+        return this[_subscription] != null;
       }
       [_add](data) {
         if (this[_isClosed]) {
           throw new core.StateError("Stream is already closed");
         }
         super._add(data);
       }
       [_addError](error, stackTrace) {
         if (this[_isClosed]) {
           throw new core.StateError("Stream is already closed");
@@ skipping 121 matching lines @@
   let _defaultHandleData = Symbol('_defaultHandleData');
   let _defaultHandleError = Symbol('_defaultHandleError');
   let _defaultHandleDone = Symbol('_defaultHandleDone');
   let _StreamHandlerTransformer$ = dart.generic(function(S, T) {
     class _StreamHandlerTransformer extends _StreamSinkTransformer$(S, T) {
       _StreamHandlerTransformer(opts) {
         let handleData = opts && 'handleData' in opts ? opts.handleData : null;
         let handleError = opts && 'handleError' in opts ? opts.handleError : null;
         let handleDone = opts && 'handleDone' in opts ? opts.handleDone : null;
         super._StreamSinkTransformer(dart.closureWrap((outputSink) => {
-          if (handleData === null)
+          if (handleData == null)
             handleData = dart.closureWrap(_StreamHandlerTransformer[_defaultHandleData], "(S, EventSink<T>) → void");
-          if (handleError === null)
+          if (handleError == null)
             handleError = dart.closureWrap(_StreamHandlerTransformer[_defaultHandleError], "(Object, StackTrace, EventSink<T>) → void");
-          if (handleDone === null)
+          if (handleDone == null)
             handleDone = _StreamHandlerTransformer[_defaultHandleDone];
           return new _HandlerEventSink(handleData, handleError, handleDone, outputSink);
         }, "(EventSink<T>) → EventSink<S>"));
       }
       bind(stream) {
         return super.bind(stream);
       }
       static [_defaultHandleData](data, sink) {
         sink.add(data);
       }
@@ skipping 91 matching lines @@
       let runBinary = opts && 'runBinary' in opts ? opts.runBinary : null;
       let registerCallback = opts && 'registerCallback' in opts ? opts.registerCallback : null;
       let registerUnaryCallback = opts && 'registerUnaryCallback' in opts ? opts.registerUnaryCallback : null;
       let registerBinaryCallback = opts && 'registerBinaryCallback' in opts ? opts.registerBinaryCallback : null;
       let errorCallback = opts && 'errorCallback' in opts ? opts.errorCallback : null;
       let scheduleMicrotask = opts && 'scheduleMicrotask' in opts ? opts.scheduleMicrotask : null;
       let createTimer = opts && 'createTimer' in opts ? opts.createTimer : null;
       let createPeriodicTimer = opts && 'createPeriodicTimer' in opts ? opts.createPeriodicTimer : null;
       let print = opts && 'print' in opts ? opts.print : null;
       let fork = opts && 'fork' in opts ? opts.fork : null;
-      return new ZoneSpecification({handleUncaughtError: dart.as(handleUncaughtError !== null ? handleUncaughtError : other.handleUncaughtError, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, dynamic, StackTrace) → dynamic")), run: dart.as(run !== null ? run : other.run, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → dynamic")), runUnary: dart.as(runUnary !== null ? runUnary : other.runUnary, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic) → dynamic, dynamic) → dynamic")), runBinary: dart.as(runBinary !== null ? runBinary : other.runBinary, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic, dynamic) → dynamic, dynamic, dynamic) → dynamic")), registerCallback: dart.as(registerCallback !== null ? registerCallback : other.registerCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → ZoneCallback")), registerUnaryCallback: dart.as(registerUnaryCallback !== null ? registerUnaryCallback : other.registerUnaryCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic) → dynamic) → ZoneUnaryCallback")), registerBinaryCallback: dart.as(registerBinaryCallback !== null ? registerBinaryCallback : other.registerBinaryCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic, dynamic) → dynamic) → ZoneBinaryCallback")), errorCallback: dart.as(errorCallback !== null ? errorCallback : other.errorCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Object, StackTrace) → AsyncError")), scheduleMicrotask: dart.as(scheduleMicrotask !== null ? scheduleMicrotask : other.scheduleMicrotask, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → void")), createTimer: dart.as(createTimer !== null ? createTimer : other.createTimer, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Duration, () → void) → Timer")), createPeriodicTimer: dart.as(createPeriodicTimer !== null ? createPeriodicTimer : other.createPeriodicTimer, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Duration, (Timer) → void) → Timer")), print: dart.as(print !== null ? print : other.print, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, String) → void")), fork: dart.as(fork !== null ? fork : other.fork, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, ZoneSpecification, Map<dynamic, dynamic>) → Zone"))});
+      return new ZoneSpecification({handleUncaughtError: dart.as(handleUncaughtError != null ? handleUncaughtError : other.handleUncaughtError, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, dynamic, StackTrace) → dynamic")), run: dart.as(run != null ? run : other.run, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → dynamic")), runUnary: dart.as(runUnary != null ? runUnary : other.runUnary, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic) → dynamic, dynamic) → dynamic")), runBinary: dart.as(runBinary != null ? runBinary : other.runBinary, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic, dynamic) → dynamic, dynamic, dynamic) → dynamic")), registerCallback: dart.as(registerCallback != null ? registerCallback : other.registerCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → ZoneCallback")), registerUnaryCallback: dart.as(registerUnaryCallback != null ? registerUnaryCallback : other.registerUnaryCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic) → dynamic) → ZoneUnaryCallback")), registerBinaryCallback: dart.as(registerBinaryCallback != null ? registerBinaryCallback : other.registerBinaryCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, (dynamic, dynamic) → dynamic) → ZoneBinaryCallback")), errorCallback: dart.as(errorCallback != null ? errorCallback : other.errorCallback, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Object, StackTrace) → AsyncError")), scheduleMicrotask: dart.as(scheduleMicrotask != null ? scheduleMicrotask : other.scheduleMicrotask, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, () → dynamic) → void")), createTimer: dart.as(createTimer != null ? createTimer : other.createTimer, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Duration, () → void) → Timer")), createPeriodicTimer: dart.as(createPeriodicTimer != null ? createPeriodicTimer : other.createPeriodicTimer, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, Duration, (Timer) → void) → Timer")), print: dart.as(print != null ? print : other.print, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, String) → void")), fork: dart.as(fork != null ? fork : other.fork, dart.throw_("Unimplemented type (Zone, ZoneDelegate, Zone, ZoneSpecification, Map<dynamic, dynamic>) → Zone"))});
     }
   }
   dart.defineNamedConstructor(ZoneSpecification, 'from');
   class _ZoneSpecification extends core.Object {
     _ZoneSpecification(opts) {
       let handleUncaughtError = opts && 'handleUncaughtError' in opts ? opts.handleUncaughtError : null;
       let run = opts && 'run' in opts ? opts.run : null;
       let runUnary = opts && 'runUnary' in opts ? opts.runUnary : null;
       let runBinary = opts && 'runBinary' in opts ? opts.runBinary : null;
       let registerCallback = opts && 'registerCallback' in opts ? opts.registerCallback : null;
@@ skipping 25 matching lines @@
   let _$ = Symbol('_');
   let _enter = Symbol('_enter');
   let _leave = Symbol('_leave');
   class Zone extends core.Object {
     [_$]() {
     }
     static get current() {
       return Zone[_current];
     }
     static [_enter](zone) {
-      dart.assert(zone !== null);
+      dart.assert(zone != null);
       dart.assert(!dart.notNull(core.identical(zone, Zone[_current])));
       let previous = Zone[_current];
       Zone[_current] = zone;
       return previous;
     }
     static [_leave](previous) {
-      dart.assert(previous !== null);
+      dart.assert(previous != null);
       Zone[_current] = previous;
     }
   }
   dart.defineNamedConstructor(Zone, _$);
   Zone.ROOT = _ROOT_ZONE;
   Zone._current = _ROOT_ZONE;
   let _delegate = Symbol('_delegate');
   // Function _parentDelegate: (_Zone) → ZoneDelegate
   function _parentDelegate(zone) {
-    if (zone.parent === null)
+    if (zone.parent == null)
       return null;
     return zone.parent[_delegate];
   }
   let _delegationTarget = Symbol('_delegationTarget');
   let _handleUncaughtError = Symbol('_handleUncaughtError');
   let _run = Symbol('_run');
   let _runUnary = Symbol('_runUnary');
   let _runBinary = Symbol('_runBinary');
   let _registerCallback = Symbol('_registerCallback');
   let _registerUnaryCallback = Symbol('_registerUnaryCallback');
@@ skipping 78 matching lines @@
     _Zone() {
     }
     inSameErrorZone(otherZone) {
       return dart.notNull(core.identical(this, otherZone)) || dart.notNull(core.identical(this.errorZone, otherZone.errorZone));
     }
   }
   let _delegateCache = Symbol('_delegateCache');
   let _map = Symbol('_map');
   class _CustomZone extends _Zone {
     get [_delegate]() {
-      if (this[_delegateCache] !== null)
+      if (this[_delegateCache] != null)
         return this[_delegateCache];
       this[_delegateCache] = new _ZoneDelegate(this);
       return this[_delegateCache];
     }
     _CustomZone(parent, specification, map) {
       this.parent = parent;
       this[_map] = map;
       this[_runUnary] = null;
       this[_run] = null;
       this[_runBinary] = null;
       this[_registerCallback] = null;
       this[_registerUnaryCallback] = null;
       this[_registerBinaryCallback] = null;
       this[_errorCallback] = null;
       this[_scheduleMicrotask] = null;
       this[_createTimer] = null;
       this[_createPeriodicTimer] = null;
       this[_print] = null;
       this[_fork] = null;
       this[_handleUncaughtError] = null;
       this[_delegateCache] = null;
       super._Zone();
-      this[_run] = specification.run !== null ? new _ZoneFunction(this, specification.run) : this.parent[_run];
-      this[_runUnary] = specification.runUnary !== null ? new _ZoneFunction(this, specification.runUnary) : this.parent[_runUnary];
-      this[_runBinary] = specification.runBinary !== null ? new _ZoneFunction(this, specification.runBinary) : this.parent[_runBinary];
-      this[_registerCallback] = specification.registerCallback !== null ? new _ZoneFunction(this, specification.registerCallback) : this.parent[_registerCallback];
-      this[_registerUnaryCallback] = specification.registerUnaryCallback !== null ? new _ZoneFunction(this, specification.registerUnaryCallback) : this.parent[_registerUnaryCallback];
-      this[_registerBinaryCallback] = specification.registerBinaryCallback !== null ? new _ZoneFunction(this, specification.registerBinaryCallback) : this.parent[_registerBinaryCallback];
-      this[_errorCallback] = specification.errorCallback !== null ? new _ZoneFunction(this, specification.errorCallback) : this.parent[_errorCallback];
-      this[_scheduleMicrotask] = specification.scheduleMicrotask !== null ? new _ZoneFunction(this, specification.scheduleMicrotask) : this.parent[_scheduleMicrotask];
-      this[_createTimer] = specification.createTimer !== null ? new _ZoneFunction(this, specification.createTimer) : this.parent[_createTimer];
-      this[_createPeriodicTimer] = specification.createPeriodicTimer !== null ? new _ZoneFunction(this, specification.createPeriodicTimer) : this.parent[_createPeriodicTimer];
-      this[_print] = specification.print !== null ? new _ZoneFunction(this, specification.print) : this.parent[_print];
-      this[_fork] = specification.fork !== null ? new _ZoneFunction(this, specification.fork) : this.parent[_fork];
-      this[_handleUncaughtError] = specification.handleUncaughtError !== null ? new _ZoneFunction(this, specification.handleUncaughtError) : this.parent[_handleUncaughtError];
+      this[_run] = specification.run != null ? new _ZoneFunction(this, specification.run) : this.parent[_run];
+      this[_runUnary] = specification.runUnary != null ? new _ZoneFunction(this, specification.runUnary) : this.parent[_runUnary];
+      this[_runBinary] = specification.runBinary != null ? new _ZoneFunction(this, specification.runBinary) : this.parent[_runBinary];
+      this[_registerCallback] = specification.registerCallback != null ? new _ZoneFunction(this, specification.registerCallback) : this.parent[_registerCallback];
+      this[_registerUnaryCallback] = specification.registerUnaryCallback != null ? new _ZoneFunction(this, specification.registerUnaryCallback) : this.parent[_registerUnaryCallback];
+      this[_registerBinaryCallback] = specification.registerBinaryCallback != null ? new _ZoneFunction(this, specification.registerBinaryCallback) : this.parent[_registerBinaryCallback];
+      this[_errorCallback] = specification.errorCallback != null ? new _ZoneFunction(this, specification.errorCallback) : this.parent[_errorCallback];
+      this[_scheduleMicrotask] = specification.scheduleMicrotask != null ? new _ZoneFunction(this, specification.scheduleMicrotask) : this.parent[_scheduleMicrotask];
+      this[_createTimer] = specification.createTimer != null ? new _ZoneFunction(this, specification.createTimer) : this.parent[_createTimer];
+      this[_createPeriodicTimer] = specification.createPeriodicTimer != null ? new _ZoneFunction(this, specification.createPeriodicTimer) : this.parent[_createPeriodicTimer];
+      this[_print] = specification.print != null ? new _ZoneFunction(this, specification.print) : this.parent[_print];
+      this[_fork] = specification.fork != null ? new _ZoneFunction(this, specification.fork) : this.parent[_fork];
+      this[_handleUncaughtError] = specification.handleUncaughtError != null ? new _ZoneFunction(this, specification.handleUncaughtError) : this.parent[_handleUncaughtError];
     }
     get errorZone() {
       return this[_handleUncaughtError].zone;
     }
     runGuarded(f) {
       try {
         return this.run(f);
       } catch (e) {
         let s = dart.stackTrace(e);
         return this.handleUncaughtError(e, s);
@@ skipping 40 matching lines @@
       let runGuarded = opts && 'runGuarded' in opts ? opts.runGuarded : true;
       let registered = this.registerBinaryCallback(f);
       if (runGuarded) {
         return ((arg1, arg2) => this.runBinaryGuarded(registered, arg1, arg2)).bind(this);
       } else {
         return ((arg1, arg2) => this.runBinary(registered, arg1, arg2)).bind(this);
       }
     }
     get(key) {
       let result = this[_map].get(key);
-      if (dart.notNull(result !== null) || dart.notNull(this[_map].containsKey(key)))
+      if (dart.notNull(result != null) || dart.notNull(this[_map].containsKey(key)))
         return result;
-      if (this.parent !== null) {
+      if (this.parent != null) {
         let value = this.parent.get(key);
-        if (value !== null) {
+        if (value != null) {
           this[_map].set(key, value);
         }
         return value;
       }
       dart.assert(dart.equals(this, _ROOT_ZONE));
       return null;
     }
     handleUncaughtError(error, stackTrace) {
       let implementation = this[_handleUncaughtError];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, error, stackTrace);
     }
     fork(opts) {
       let specification = opts && 'specification' in opts ? opts.specification : null;
       let zoneValues = opts && 'zoneValues' in opts ? opts.zoneValues : null;
       let implementation = this[_fork];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, specification, zoneValues), Zone);
     }
     run(f) {
       let implementation = this[_run];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f);
     }
     runUnary(f, arg) {
       let implementation = this[_runUnary];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f, arg);
     }
     runBinary(f, arg1, arg2) {
       let implementation = this[_runBinary];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f, arg1, arg2);
     }
     registerCallback(f) {
       let implementation = this[_registerCallback];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f), ZoneCallback);
     }
     registerUnaryCallback(f) {
       let implementation = this[_registerUnaryCallback];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f), ZoneUnaryCallback);
     }
     registerBinaryCallback(f) {
       let implementation = this[_registerBinaryCallback];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f), ZoneBinaryCallback);
     }
     errorCallback(error, stackTrace) {
       let implementation = this[_errorCallback];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let implementationZone = implementation.zone;
       if (core.identical(implementationZone, _ROOT_ZONE))
         return null;
       let parentDelegate = _parentDelegate(dart.as(implementationZone, _Zone));
       return dart.as(dart.dinvokef(implementation.function, implementationZone, parentDelegate, this, error, stackTrace), AsyncError);
     }
     scheduleMicrotask(f) {
       let implementation = this[_scheduleMicrotask];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, f);
     }
     createTimer(duration, f) {
       let implementation = this[_createTimer];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, duration, f), Timer);
     }
     createPeriodicTimer(duration, f) {
       let implementation = this[_createPeriodicTimer];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.as(dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, duration, f), Timer);
     }
     print(line) {
       let implementation = this[_print];
-      dart.assert(implementation !== null);
+      dart.assert(implementation != null);
       let parentDelegate = _parentDelegate(implementation.zone);
       return dart.dinvokef(implementation.function, implementation.zone, parentDelegate, this, line);
     }
   }
   // Function _rootHandleUncaughtError: (Zone, ZoneDelegate, Zone, dynamic, StackTrace) → void
   function _rootHandleUncaughtError(self, parent, zone, error, stackTrace) {
     _schedulePriorityAsyncCallback(() => {
       throw new _UncaughtAsyncError(error, stackTrace);
     });
   }
@@ skipping 72 matching lines @@
   function _rootPrint(self, parent, zone, line) {
     _internal.printToConsole(line);
   }
   // Function _printToZone: (String) → void
   function _printToZone(line) {
     Zone.current.print(line);
   }
   // Function _rootFork: (Zone, ZoneDelegate, Zone, ZoneSpecification, Map<dynamic, dynamic>) → Zone
   function _rootFork(self, parent, zone, specification, zoneValues) {
     _internal.printToZone = _printToZone;
-    if (specification === null) {
+    if (specification == null) {
       specification = new ZoneSpecification();
     } else if (!dart.is(specification, _ZoneSpecification)) {
       throw new core.ArgumentError("ZoneSpecifications must be instantiated" + " with the provided constructor.");
     }
     let valueMap = null;
-    if (zoneValues === null) {
+    if (zoneValues == null) {
       if (dart.is(zone, _Zone)) {
         valueMap = zone[_map];
       } else {
         valueMap = new collection.HashMap();
       }
     } else {
       valueMap = new collection.HashMap.from(zoneValues);
     }
     return new _CustomZone(dart.as(zone, _Zone), specification, valueMap);
   }
@@ skipping 83 matching lines @@
     get [_handleUncaughtError]() {
       return new _ZoneFunction(_ROOT_ZONE, _rootHandleUncaughtError);
     }
     get parent() {
       return null;
     }
     get [_map]() {
       return _RootZone[_rootMap];
     }
     get [_delegate]() {
-      if (_RootZone[_rootDelegate] !== null)
+      if (_RootZone[_rootDelegate] != null)
         return _RootZone[_rootDelegate];
       return _RootZone[_rootDelegate] = new _ZoneDelegate(this);
     }
     get errorZone() {
       return this;
     }
     runGuarded(f) {
       try {
         if (core.identical(_ROOT_ZONE, Zone[_current])) {
           return f();
@@ skipping 111 matching lines @@
     },
     set _rootMap(_) {}
   });
   let _ROOT_ZONE = new _RootZone();
   // Function runZoned: (() → dynamic, {zoneValues: Map<dynamic, dynamic>, zoneSpecification: ZoneSpecification, onError: Function}) → dynamic
   function runZoned(body, opts) {
     let zoneValues = opts && 'zoneValues' in opts ? opts.zoneValues : null;
     let zoneSpecification = opts && 'zoneSpecification' in opts ? opts.zoneSpecification : null;
     let onError = opts && 'onError' in opts ? opts.onError : null;
     let errorHandler = null;
-    if (onError !== null) {
+    if (onError != null) {
       errorHandler = (self, parent, zone, error, stackTrace) => {
         try {
           if (dart.is(onError, ZoneBinaryCallback)) {
             return self.parent.runBinary(onError, error, stackTrace);
           }
           return self.parent.runUnary(dart.as(onError, dart.throw_("Unimplemented type (dynamic) → dynamic")), error);
         } catch (e) {
           let s = dart.stackTrace(e);
           if (core.identical(e, error)) {
             return parent.handleUncaughtError(zone, error, stackTrace);
           } else {
             return parent.handleUncaughtError(zone, e, s);
           }
         }
 
       };
     }
-    if (zoneSpecification === null) {
+    if (zoneSpecification == null) {
       zoneSpecification = new ZoneSpecification({handleUncaughtError: errorHandler});
-    } else if (errorHandler !== null) {
+    } else if (errorHandler != null) {
       zoneSpecification = new ZoneSpecification.from(zoneSpecification, {handleUncaughtError: errorHandler});
     }
     let zone = Zone.current.fork({specification: zoneSpecification, zoneValues: zoneValues});
-    if (onError !== null) {
+    if (onError != null) {
       return zone.runGuarded(body);
     } else {
       return zone.run(body);
     }
   }
   dart.copyProperties(exports, {
     get _hasDocument() {
-      return dart.equals(typeof document, 'object');
+      return typeof document == 'object';
     }
   });
   // Exports:
   exports.AsyncError = AsyncError;
   exports.Stream = Stream;
   exports.Stream$ = Stream$;
   exports.DeferredLibrary = DeferredLibrary;
   exports.DeferredLoadException = DeferredLoadException;
   exports.Future = Future;
   exports.Future$ = Future$;
@@ skipping 16 matching lines @@
   exports.StreamIterator = StreamIterator;
   exports.StreamIterator$ = StreamIterator$;
   exports.StreamController = StreamController;
   exports.StreamController$ = StreamController$;
   exports.Timer = Timer;
   exports.ZoneSpecification = ZoneSpecification;
   exports.ZoneDelegate = ZoneDelegate;
   exports.Zone = Zone;
   exports.runZoned = runZoned;
 })(async || (async = {}));