Don't generate forwarding hooks if all noSuchMethod implementations

pkg/compiler/lib/src/js_backend/backend.dart

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index 08fa0a74db29be482239a6f7e62b6111c4bfc36d..1af1fd46cd1b719c4399db04621d48ed8e7639d4 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -585,6 +585,9 @@ class JavaScriptBackend extends Backend {
   /// constructors for custom elements.
   CustomElementsAnalysis customElementsAnalysis;
 
+  /// Support for classifying `noSuchMethod` implementations.
+  NoSuchMethodAnalysis noSuchMethodAnalysis;
+
   JavaScriptConstantTask constantCompilerTask;
 
   JavaScriptResolutionCallbacks resolutionCallbacks;
@@ -603,6 +606,7 @@ class JavaScriptBackend extends Backend {
     emitter = new CodeEmitterTask(compiler, namer, generateSourceMap);
     typeVariableHandler = new TypeVariableHandler(this);
     customElementsAnalysis = new CustomElementsAnalysis(this);
+    noSuchMethodAnalysis = new NoSuchMethodAnalysis(this);
     constantCompilerTask = new JavaScriptConstantTask(compiler);
     resolutionCallbacks = new JavaScriptResolutionCallbacks(this);
     patchResolverTask = new PatchResolverTask(compiler);
@@ -1206,11 +1210,13 @@ class JavaScriptBackend extends Backend {
     enqueueClass(compiler.enqueuer.resolution, compiler.stringClass, registry);
   }
 
-  void enableNoSuchMethod(Element context, Enqueuer world) {
+  void registerNoSuchMethod(Element noSuchMethod, Enqueuer enqueuer) {
+    noSuchMethodAnalysis.registerNoSuchMethod(noSuchMethod);
+  }
+
+  void enableNoSuchMethod(Enqueuer world) {
     enqueue(world, getCreateInvocationMirror(), compiler.globalDependencies);
     world.registerInvocation(compiler.noSuchMethodSelector);
-    // TODO(tyoverby): Send the context element to DumpInfoTask to be
-    // blamed.
   }
 
   void enableIsolateSupport(Enqueuer enqueuer) {
@@ -2399,6 +2405,8 @@ class JavaScriptBackend extends Backend {
     customElementsAnalysis.onQueueEmpty(enqueuer);
     if (!enqueuer.queueIsEmpty) return false;
 
+    noSuchMethodAnalysis.onQueueEmpty(enqueuer);
+
     if (compiler.hasIncrementalSupport) {
       // Always enable tear-off closures during incremental compilation.
       Element e = findHelper('closureFromTearOff');