New implementation of {,Linked}Hash{Set,Map}.

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index ff825977bfcf8fe92601ad37f9915534502b38f1..88ff9c0a1f9948e4d64909a04144d9857eada8c0 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -306,7 +306,7 @@ class FieldTypesRegistry {
     // TODO(sgjesse): Handle field types for classes with more than one
     // constructor.
     if (ctors.length == 2) {
-      optimizedFunctions.forEach((Element field, _) {
+      new Map.from(optimizedFunctions).forEach((Element field, _) {
         if (identical(field.enclosingElement, cls)) {
           scheduleRecompilation(field);
         }
@@ -347,12 +347,12 @@ class FieldTypesRegistry {
     // TODO(sgjesse): Take the type of the setter into account.
     if (setterSelectorsUsed.contains(setter.name)) return;
     setterSelectorsUsed.add(setter.name);
-    optimizedStaticFunctions.forEach((Element field, _) {
+    new Map.from(optimizedStaticFunctions).forEach((Element field, _) {
       if (field.name == setter.name) {
         scheduleRecompilation(field);
       }
     });
-    optimizedFunctions.forEach((Element field, _) {
+    new Map.from(optimizedFunctions).forEach((Element field, _) {
       if (field.name == setter.name) {
         scheduleRecompilation(field);
       }
@@ -897,7 +897,7 @@ class JavaScriptBackend extends Backend {
       // The backend will use a literal list to initialize the entries
       // of the map.
       if (enqueuer.isResolutionQueue) {
-        enqueuer.registerInstantiatedClass(compiler.listClass); 
+        enqueuer.registerInstantiatedClass(compiler.listClass);
       }
     }
   }