Fix compilation failure on Win64 since r14020.

src/heap.cc

 // Copyright 2012 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 3862 matching lines @@
     maybe_result = code_space_->AllocateRaw(new_obj_size);
   }
 
   Object* result;
   if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // Copy code object.
   Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
 
   // Copy header and instructions.
-  CopyBytes(new_addr, old_addr, relocation_offset);
+  CopyBytes(new_addr, old_addr, static_cast<int>(relocation_offset));
 
   Code* new_code = Code::cast(result);
   new_code->set_relocation_info(ByteArray::cast(reloc_info_array));
 
   // Copy patched rinfo.
   CopyBytes(new_code->relocation_start(),
             reloc_info.start(),
             reloc_info.length());
 
   // Relocate the copy.
@@ skipping 3918 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   memcpy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   memcpy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal