Refactor visitSendSet for super compounds and assignment.

pkg/compiler/lib/src/js_backend/backend.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 js_backend;
 
 const VERBOSE_OPTIMIZER_HINTS = false;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked = new Set<HInstruction>();
@@ skipping 2962 matching lines @@
   }
 
   void onSuperNoSuchMethod(Registry registry) {
     assert(registry.isForResolution);
     registerBackendStaticInvocation(
         backend.getCreateInvocationMirror(), registry);
     registerBackendStaticInvocation(
         backend.compiler.objectClass.lookupLocalMember(Compiler.NO_SUCH_METHOD),
         registry);
     registerBackendInstantiation(backend.compiler.listClass, registry);
+    registerBackendInstantiation(backend.compiler.stringClass, registry);
   }
 
   void onMapLiteral(ResolutionRegistry registry,
                     DartType type,
                     bool isConstant) {
     assert(registry.isForResolution);
     void enqueue(String name) {
       Element e = backend.find(backend.jsHelperLibrary, name);
       registerBackendInstantiation(e, registry);
     }
@@ skipping 18 matching lines @@
   }
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }