Add a new implementation of HashMap that uses JS objects for its (multiple) hash tables.

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 991 matching lines @@
   // The corresponding type, the "unknown type", is stored in the object store.
   cls = dynamic_class();
   type = Type::NewNonParameterizedType(cls);
   object_store->set_dynamic_type(type);
 
   // Finish the initialization by compiling the bootstrap scripts containing the
   // base interfaces and the implementation of the internal classes.
   INIT_LIBRARY(Core, core, true);
 
   INIT_LIBRARY(Async, async, true);
-  INIT_LIBRARY(Collection, collection, false);
+  INIT_LIBRARY(Collection, collection, true);
   INIT_LIBRARY(CollectionDev, collection_dev, false);
   INIT_LIBRARY(Crypto, crypto, false);
   INIT_LIBRARY(Isolate, isolate, true);
   INIT_LIBRARY(Json, json, true);
   INIT_LIBRARY(Math, math, true);
   INIT_LIBRARY(Mirrors, mirrors, true);
   INIT_LIBRARY(Scalarlist, scalarlist, true);
   INIT_LIBRARY(TypedData, typeddata, true);
   INIT_LIBRARY(Utf, utf, false);
   INIT_LIBRARY(Uri, uri, false);
@@ skipping 12595 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart