Add a new interceptor class JsArray, and support intercepting some list methods with the new interc…

sdk/lib/_internal/compiler/implementation/enqueue.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.
 
 part of dart2js;
 
 class EnqueueTask extends CompilerTask {
   final Enqueuer codegen;
   final Enqueuer resolution;
 
@@ skipping 120 matching lines @@
    * Invariant: [element] must be a declaration element.
    */
   void eagerRecompile(Element element) {
     assert(invariant(element, element.isDeclaration));
     universe.generatedCode.remove(element);
     universe.generatedBailoutCode.remove(element);
     addToWorkList(element);
   }
 
   void registerInstantiatedClass(ClassElement cls) {
-    if (cls.isInterface()) {
-      compiler.internalErrorOnElement(
-          // Use the current element, as this is where cls is referenced from.
-          compiler.currentElement,
-          'Expected a class, but $cls is an interface.');
-    }
     universe.instantiatedClasses.add(cls);
     onRegisterInstantiatedClass(cls);
     compiler.backend.registerInstantiatedClass(cls, this);
   }
 
   bool checkNoEnqueuedInvokedInstanceMethods() {
     task.measure(() {
       // Run through the classes and see if we need to compile methods.
       for (ClassElement classElement in universe.instantiatedClasses) {
         for (ClassElement currentClass = classElement;
@@ skipping 75 matching lines @@
       // The class must be resolved to compute the set of all
       // supertypes.
       cls.ensureResolved(compiler);
 
       for (Link<DartType> supertypes = cls.allSupertypesAndSelf;
            !supertypes.isEmpty; supertypes = supertypes.tail) {
         cls = supertypes.head.element;
         if (seenClasses.contains(cls)) continue;
         seenClasses.add(cls);
         cls.ensureResolved(compiler);
-        if (!cls.isInterface()) {
-          cls.implementation.forEachMember(processInstantiatedClassMember);
-        }
+        cls.implementation.forEachMember(processInstantiatedClassMember);
         if (isResolutionQueue) {
           compiler.resolver.checkMembers(cls);
         }
 
         if (compiler.enableTypeAssertions) {
           // We need to register is checks and helpers for checking
           // assignments to fields.
           // TODO(ngeoffray): This should really move to the backend.
           cls.localMembers.forEach((Element member) {
             if (!member.isInstanceMember() || !member.isField()) return;
@@ skipping 157 matching lines @@
     nativeEnqueuer.logSummary(log);
   }
 
   registerUsedSelector(Selector selector) {
     Element interceptor = compiler.backend.getInterceptor(selector);
     if (interceptor != null) {
       registerStaticUse(interceptor);
     }
   }
 }