Share the JavaScript based LinkedHashMap implementation between constant maps and the LinkedHashMap…

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;
 
 const bool USE_CPS_IR = const bool.fromEnvironment("USE_CPS_IR");
 
@@ skipping 2652 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);
   }
 
-  void onConstantMap(Registry 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);
     }
 
-    enqueue(JavaScriptMapConstant.DART_CLASS);
-    enqueue(JavaScriptMapConstant.DART_PROTO_CLASS);
-    enqueue(JavaScriptMapConstant.DART_STRING_CLASS);
-    enqueue(JavaScriptMapConstant.DART_GENERAL_CLASS);
+    if (isConstant) {
+      enqueue(JavaScriptMapConstant.DART_CLASS);
+      enqueue(JavaScriptMapConstant.DART_PROTO_CLASS);
+      enqueue(JavaScriptMapConstant.DART_STRING_CLASS);
+      enqueue(JavaScriptMapConstant.DART_GENERAL_CLASS);
+    } else {
+      registry.registerInstantiatedType(type);
+    }
   }
 
   /// Called when resolving the `Symbol` constructor.
   void onSymbolConstructor(Registry registry) {
     assert(registry.isForResolution);
     // Make sure that _internals.Symbol.validated is registered.
     assert(backend.compiler.symbolValidatedConstructor != null);
     registerBackendStaticInvocation(
         backend.compiler.symbolValidatedConstructor, registry);
   }
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }