emit interfaces before use

lib/runtime/dart/isolate.js

 var isolate;
 (function(exports) {
   'use strict';
   class Capability extends core.Object {
     Capability() {
       return new _isolate_helper.CapabilityImpl();
     }
   }
   class IsolateSpawnException extends core.Object {
     IsolateSpawnException(message) {
@@ skipping 137 matching lines @@
     }
   }
   Isolate.IMMEDIATE = 0;
   Isolate.BEFORE_NEXT_EVENT = 1;
   Isolate.AS_EVENT = 2;
   dart.defineLazyProperties(Isolate, {
     get _currentIsolateCache() {
       return _isolate_helper.IsolateNatives.currentIsolate;
     }
   });
-  class SendPort extends core.Object {
-  }
+  class SendPort extends core.Object {}
   SendPort[dart.implements] = [Capability];
-  class ReceivePort extends core.Object {
-    ReceivePort() {
-      return new _isolate_helper.ReceivePortImpl();
+  dart.defineLazyClass(exports, {
+    get ReceivePort() {
+      class ReceivePort extends core.Object {
+        ReceivePort() {
+          return new _isolate_helper.ReceivePortImpl();
+        }
+        fromRawReceivePort(rawPort) {
+          return new _isolate_helper.ReceivePortImpl.fromRawReceivePort(rawPort);
+        }
+      }
+      ReceivePort[dart.implements] = [async.Stream];
+      dart.defineNamedConstructor(ReceivePort, 'fromRawReceivePort');
+      return ReceivePort;
     }
-    fromRawReceivePort(rawPort) {
-      return new _isolate_helper.ReceivePortImpl.fromRawReceivePort(rawPort);
-    }
-  }
-  ReceivePort[dart.implements] = [async.Stream];
-  dart.defineNamedConstructor(ReceivePort, 'fromRawReceivePort');
+  });
   class RawReceivePort extends core.Object {
     RawReceivePort(handler) {
       if (handler === void 0)
         handler = null;
       return new _isolate_helper.RawReceivePortImpl(handler);
     }
   }
   class _IsolateUnhandledException extends core.Object {
     _IsolateUnhandledException(message, source, stackTrace) {
       this.message = message;
@@ skipping 24 matching lines @@
     toString() {
       return this[_trace];
     }
   }
   _RemoteStackTrace[dart.implements] = [core.StackTrace];
   // Exports:
   exports.Capability = Capability;
   exports.IsolateSpawnException = IsolateSpawnException;
   exports.Isolate = Isolate;
   exports.SendPort = SendPort;
-  exports.ReceivePort = ReceivePort;
   exports.RawReceivePort = RawReceivePort;
   exports.RemoteError = RemoteError;
 })(isolate || (isolate = {}));