Fix warnings on Win64.

src/scopes.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 24 matching lines @@
 namespace internal {
 
 // ----------------------------------------------------------------------------
 // A Zone allocator for use with LocalsMap.
 
 class ZoneAllocator: public Allocator {
  public:
   /* nothing to do */
   virtual ~ZoneAllocator()  {}
 
-  virtual void* New(size_t size)  { return Zone::New(size); }
+  virtual void* New(size_t size)  { return Zone::New(static_cast<int>(size)); }
 
   /* ignored - Zone is freed in one fell swoop */
   virtual void Delete(void* p)  {}
 };
 
 
 static ZoneAllocator LocalsMapAllocator;
 
 
 // ----------------------------------------------------------------------------
@@ skipping 899 matching lines @@
   if (num_heap_slots_ == Context::MIN_CONTEXT_SLOTS &&
       !must_have_local_context) {
     num_heap_slots_ = 0;
   }
 
   // Allocation done.
   ASSERT(num_heap_slots_ == 0 || num_heap_slots_ >= Context::MIN_CONTEXT_SLOTS);
 }
 
 } }  // namespace v8::internal