Move creation of collection prototypes into JavaScript.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index a7c2bac25d61bd0987c33b08d9e8ea26fba4d6aa..d071f45da96dbd10df3cf8107c124f8df9877315 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1275,31 +1275,27 @@ void Genesis::InitializeExperimentalGlobal() {
 
   if (FLAG_harmony_collections) {
     {  // -- S e t
-      Handle<JSObject> prototype =
-          factory()->NewJSObject(isolate()->object_function(), TENURED);
       InstallFunction(global, "Set", JS_SET_TYPE, JSSet::kSize,
-                      prototype, Builtins::kIllegal, true);
+                      isolate()->initial_object_prototype(),
+                      Builtins::kIllegal, true);
     }
     {  // -- M a p
-      Handle<JSObject> prototype =
-          factory()->NewJSObject(isolate()->object_function(), TENURED);
       InstallFunction(global, "Map", JS_MAP_TYPE, JSMap::kSize,
-                      prototype, Builtins::kIllegal, true);
+                      isolate()->initial_object_prototype(),
+                      Builtins::kIllegal, true);
     }
     {  // -- W e a k M a p
-      Handle<JSObject> prototype =
-          factory()->NewJSObject(isolate()->object_function(), TENURED);
       InstallFunction(global, "WeakMap", JS_WEAK_MAP_TYPE, JSWeakMap::kSize,
-                      prototype, Builtins::kIllegal, true);
+                      isolate()->initial_object_prototype(),
+                      Builtins::kIllegal, true);
     }
   }
 
   if (FLAG_harmony_typed_arrays) {
-    { // -- A r r a y B u f f e r
-      Handle<JSObject> prototype =
-          factory()->NewJSObject(isolate()->object_function(), TENURED);
+    {  // -- A r r a y B u f f e r
       InstallFunction(global, "__ArrayBuffer", JS_ARRAY_BUFFER_TYPE,
-                      JSArrayBuffer::kSize, prototype,
+                      JSArrayBuffer::kSize,
+                      isolate()->initial_object_prototype(),
                       Builtins::kIllegal, true);
     }
   }