Cleanup of various DOM dart2js and dart_analyzer warnings

sdk/lib/html/dart2js/html_dart2js.dart

 /// The Dart HTML library.
 library dart.dom.html;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:_collection-dev' hide Symbol;
 import 'dart:html_common';
 import 'dart:indexed_db';
 import 'dart:isolate';
 import 'dart:json' as json;
@@ skipping 7642 matching lines @@
     } else if (JS('bool', '!!#.webkitMatchesSelector', this)) {
       return JS('bool', '#.webkitMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.mozMatchesSelector', this)) {
       return JS('bool', '#.mozMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.msMatchesSelector', this)) {
       return JS('bool', '#.msMatchesSelector(#)', this, selectors);
     }
     throw new UnsupportedError("Not supported on this platform");
   }
 
-  @Creates('Null')
+  @Creates('Null') // Set from Dart code; does not instantiate a native type.
   Map<String, StreamSubscription> _attributeBindings;
 
   // TODO(jmesserly): I'm concerned about adding these to every element.
   // Conceptually all of these belong on TemplateElement. They are here to
   // support browsers that don't have <template> yet.
   // However even in the polyfill they're restricted to certain tags
   // (see [isTemplate]). So we can probably convert it to a (public) mixin, and
   // only mix it in to the elements that need it.
   @Creates('Null')  // Set from Dart code; does not instantiate a native type.
   var _model;
@@ skipping 6887 matching lines @@
    * after the event has fired or if the element has CSS transforms affecting
    * it.
    */
   Point get offset {
     if (JS('bool', '!!#.offsetX', this)) {
       var x = JS('int', '#.offsetX', this);
       var y = JS('int', '#.offsetY', this);
       return new Point(x, y);
     } else {
       // Firefox does not support offsetX.
-      var target = this.target;
-      if (!(target is Element)) {
+      if (!(this.target is Element)) {
         throw new UnsupportedError(
             'offsetX is only supported on elements');
       }
-      return (this.client -
-          this.target.getBoundingClientRect().topLeft).toInt();
+      Element target = this.target;
+      return (this.client - target.getBoundingClientRect().topLeft).toInt();
     }
   }
 
   @DomName('MouseEvent.screenX')
   @DomName('MouseEvent.screenY')
   Point get screen => new Point($dom_screenX, $dom_screenY);
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
@@ skipping 532 matching lines @@
     if (l > 1) throw new StateError("More than one element");
     return JS('Node|Null', '#.firstChild', _this);
   }
 
   void add(Node value) {
     _this.append(value);
   }
 
   void addAll(Iterable<Node> iterable) {
     if (iterable is _ChildNodeListLazy) {
-      if (!identical(iterable._this, _this)) {
+      _ChildNodeListLazy otherList = iterable;
+      if (!identical(otherList._this, _this)) {
         // Optimized route for copying between nodes.
-        for (var i = 0, len = iterable.length; i < len; ++i) {
+        for (var i = 0, len = otherList.length; i < len; ++i) {
           // Should use $dom_firstChild, Bug 8886.
-          _this.append(iterable[0]);
+          _this.append(otherList[0]);
         }
       }
       return;
     }
     for (Node node in iterable) {
       _this.append(node);
     }
   }
 
   void insert(int index, Node node) {
@@ skipping 9298 matching lines @@
   void pause([Future resumeSignal]) {
     if (_canceled) return;
     ++_pauseCount;
     _unlisten();
 
     if (resumeSignal != null) {
       resumeSignal.whenComplete(resume);
     }
   }
 
-  bool get _paused => _pauseCount > 0;
+  bool get isPaused => _pauseCount > 0;
 
   void resume() {
-    if (_canceled || !_paused) return;
+    if (_canceled || !isPaused) return;
     --_pauseCount;
     _tryResume();
   }
 
   void _tryResume() {
-    if (_onData != null && !_paused) {
+    if (_onData != null && !isPaused) {
       _target.$dom_addEventListener(_eventType, _onData, _useCapture);
     }
   }
 
   void _unlisten() {
     if (_onData != null) {
       _target.$dom_removeEventListener(_eventType, _onData, _useCapture);
     }
   }
 
@@ skipping 103 matching lines @@
   }
 
   E removeAt(int pos) {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
   E removeLast() {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
-  void remove(Object object) {
+  bool remove(Object object) {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
   void removeWhere(bool test(E element)) {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
   void retainWhere(bool test(E element)) {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
-  void setRange(int start, int end, Iterable<E> iterable, [int skipCount]) {
+  void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) {
     throw new UnsupportedError("Cannot setRange on immutable List.");
   }
 
   void removeRange(int start, int end) {
     throw new UnsupportedError("Cannot removeRange on immutable List.");
   }
 
   void replaceRange(int start, int end, Iterable<E> iterable) {
     throw new UnsupportedError("Cannot modify an immutable List.");
   }
@@ skipping 2051 matching lines @@
       }
     }
 
     for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
       clone.append(_createDeepCloneAndDecorateTemplates(c, syntax));
     }
     return clone;
   }
 
   // http://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/templates/index.html#dfn-template-contents-owner
-  static Document _getTemplateContentsOwner(Document doc) {
+  static Document _getTemplateContentsOwner(HtmlDocument doc) {
     if (doc.window == null) {
       return doc;
     }
     var d = doc._templateContentsOwner;
     if (d == null) {
       // TODO(arv): This should either be a Document or HTMLDocument depending
       // on doc.
       d = doc.implementation.createHtmlDocument('');
       while (d.$dom_lastChild != null) {
         d.$dom_lastChild.remove();
@@ skipping 57 matching lines @@
     void bootstrap(template) {
       if (!TemplateElement.decorate(template)) {
         _bootstrapTemplatesRecursivelyFrom(template.content);
       }
     }
 
     // Need to do this first as the contents may get lifted if |node| is
     // template.
     // TODO(jmesserly): node is DocumentFragment or Element
     var descendents = (node as dynamic).queryAll(_allTemplatesSelectors);
-    if (node is Element && node.isTemplate) bootstrap(node);
+    if (node is Element && (node as Element).isTemplate) bootstrap(node);
 
     descendents.forEach(bootstrap);
   }
 
   static final String _allTemplatesSelectors = 'template, option[template], ' +
       Element._TABLE_TAGS.keys.map((k) => "$k[template]").join(", ");
 
   static void _addBindings(Node node, model, [CustomBindingSyntax syntax]) {
     if (node is Element) {
       _addAttributeBindings(node, model, syntax);
@@ skipping 133 matching lines @@
 
   static void _removeAllBindingsRecursively(Node node) {
     _nodeOrCustom(node).unbindAll();
     for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
       _removeAllBindingsRecursively(c);
     }
   }
 
   static void _removeChild(Node parent, Node child) {
     child._templateInstance = null;
-    if (child is Element && child.isTemplate) {
+    if (child is Element && (child as Element).isTemplate) {
       // Make sure we stop observing when we remove an element.
       var templateIterator = child._templateIterator;
       if (templateIterator != null) {
         templateIterator.abandon();
         child._templateIterator = null;
       }
     }
     child.remove();
     _removeAllBindingsRecursively(child);
   }
@@ skipping 814 matching lines @@
   // Iterable APIs
 
   Iterator<E> get iterator => new _WrappedIterator(_list.iterator);
 
   int get length => _list.length;
 
   // Collection APIs
 
   void add(E element) { _list.add(element); }
 
-  void remove(Object element) { _list.remove(element); }
+  bool remove(Object element) => _list.remove(element);
 
   void clear() { _list.clear(); }
 
   // List APIs
 
   E operator [](int index) => _list[index];
 
   void operator []=(int index, E value) { _list[index] = value; }
 
   void set length(int newLength) { _list.length = newLength; }
@@ skipping 114 matching lines @@
   return _DOMWindowCrossFrame._createSafe(win);
 }
 
 EventTarget _convertNativeToDart_EventTarget(e) {
   if (e == null) {
     return null;
   }
   // Assume it's a Window if it contains the setInterval property.  It may be
   // from a different frame - without a patched prototype - so we cannot
   // rely on Dart type checking.
-  if (JS('bool', r'"setInterval" in #', e))
-    return _DOMWindowCrossFrame._createSafe(e);
+  if (JS('bool', r'"setInterval" in #', e)) {
+    var window = _DOMWindowCrossFrame._createSafe(e);
+    // If it's a native window.
+    if (window is EventTarget) {
+      return window;
+    }
+    return null;
+  }
   else
     return e;
 }
 
 EventTarget _convertDartToNative_EventTarget(e) {
   if (e is _DOMWindowCrossFrame) {
     return e._window;
   } else {
     return e;
   }
@@ skipping 412 matching lines @@
       _position = nextPosition;
       return true;
     }
     _current = null;
     _position = _array.length;
     return false;
   }
 
   T get current => _current;
 }