Use weak cell in monomorphic KeyedStore IC.

src/ic/ic-compiler.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/ic/handler-compiler.h"
 #include "src/ic/ic-inl.h"
 #include "src/ic/ic-compiler.h"
 
@@ skipping 433 matching lines @@
   Handle<Code> stub;
   if (receiver_map->has_fast_elements() ||
       receiver_map->has_external_array_elements() ||
       receiver_map->has_fixed_typed_array_elements()) {
     stub = StoreFastElementStub(isolate(), is_jsarray, elements_kind,
                                 store_mode).GetCode();
   } else {
     stub = StoreElementStub(isolate(), elements_kind).GetCode();
   }
 
-  __ DispatchMap(receiver(), scratch1(), receiver_map, stub, DO_SMI_CHECK);
+  Handle<WeakCell> cell = Map::WeakCellForMap(receiver_map);
+
+  __ DispatchWeakMap(receiver(), scratch1(), scratch2(), cell, stub,
+                     DO_SMI_CHECK);
 
   TailCallBuiltin(masm(), Builtins::kKeyedStoreIC_Miss);
 
   return GetCode(kind(), Code::NORMAL, factory()->empty_string());
 }
 
 
 #undef __
 }
 }  // namespace v8::internal