Don't generate forwarding hooks if all noSuchMethod implementations

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index c26087dc10523cce49a3b4959a4d68b82c995ee3..6d65c50cd9960ada7fd49a5284d66dc71a783b2f 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -362,10 +362,20 @@ abstract class Backend {
   void registerRuntimeType(Enqueuer enqueuer, Registry registry) {}
 
   /**
+   * Call this to register a `noSuchMethod` implementation.
+   */
+  void registerNoSuchMethod(Element noSuchMethodElement, Enqueuer enqueuer) {

[Johnni Winther, 2015/03/16 14:20:43]

Leave the default implementation empty. Only the JS backend cares about this.

[Harry Terkelsen, 2015/03/17 21:43:11]

Done.

+    if (compiler.enabledNoSuchMethod) return;
+    if (isDefaultNoSuchMethodImplementation(noSuchMethodElement)) return;
+    enableNoSuchMethod(enqueuer);
+    compiler.enabledNoSuchMethod = true;

[floitsch, 2015/03/13 15:51:49]

I would have expected this to be in `enableNoSuchMethod`.

What's the semantics of "Compiler.enabledNoSuchMethod" ?
Could we keep it in the backend?

[Johnni Winther, 2015/03/16 14:20:43]

Add a TODO on Compiler.enabledNoSuchMethod to move it to the JS backend.

[Harry Terkelsen, 2015/03/17 21:43:11]

It is just a flag that says if noSuchMethod support is enabled. It is only used
by the JS backend. I moved the flag to the backend

[Harry Terkelsen, 2015/03/17 21:43:11]

I just moved it

+  }
+
+  /**
    * Call this method to enable [noSuchMethod] handling in the
    * backend.
    */
-  void enableNoSuchMethod(Element context, Enqueuer enqueuer) {
+  void enableNoSuchMethod(Enqueuer enqueuer) {

[floitsch, 2015/03/13 15:51:49]

Can we remove this method? (or make it private)

[Harry Terkelsen, 2015/03/17 21:43:11]

Done.

     enqueuer.registerInvocation(compiler.noSuchMethodSelector);
   }
 
@@ -1627,7 +1637,7 @@ abstract class Compiler implements DiagnosticListener {
       backend.enableIsolateSupport(enqueuer.codegen);
     }
     if (enabledNoSuchMethod) {
-      backend.enableNoSuchMethod(null, enqueuer.codegen);
+      backend.enableNoSuchMethod(enqueuer.codegen);
     }
     if (compileAll) {
       libraryLoader.libraries.forEach((LibraryElement library) {