Reapply 'Add runtimeType() to Object which returns canonicalized instances of Type'.

lib/compiler/implementation/js_backend/emitter.dart

 // 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.
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
 class ClosureInvocationElement extends FunctionElement {
   ClosureInvocationElement(SourceString name,
@@ skipping 1293 matching lines @@
       emitStaticFunctions(mainBuffer);
       emitStaticFunctionGetters(mainBuffer);
       // We need to finish the classes before we construct compile time
       // constants.
       emitFinishClassesInvocationIfNecessary(mainBuffer);
       emitCompileTimeConstants(mainBuffer);
       // Static field initializations require the classes and compile-time
       // constants to be set up.
       emitStaticNonFinalFieldInitializations(mainBuffer);
       emitLazilyInitializedStaticFields(mainBuffer);
+      if (compiler.enabledRuntimeType) {
+        mainBuffer.add('$isolateProperties.runtimeTypeCache = {};\n');
+      }
 
       isolateProperties = isolatePropertiesName;
       // The following code should not use the short-hand for the
       // initialStatics.
       mainBuffer.add('var ${namer.CURRENT_ISOLATE} = null;\n');
       mainBuffer.add(boundClosureBuffer);
       emitFinishClassesInvocationIfNecessary(mainBuffer);
       // After this assignment we will produce invalid JavaScript code if we use
       // the classesCollector variable.
       classesCollector = 'classesCollector should not be used from now on';
@@ skipping 37 matching lines @@
 const String HOOKS_API_USAGE = """
 // Generated by dart2js, the Dart to JavaScript compiler.
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;