Fix presubmit failure in r11376.

include/v8.h

 // 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 3957 matching lines @@
     return representation == kExternalTwoByteRepresentationTag;
   }
 
   static inline bool IsInitialized(v8::Isolate* isolate) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) + kIsolateStateOffset;
     return *reinterpret_cast<int*>(addr) == 1;
   }
 
   static inline internal::Object** GetRoot(v8::Isolate* isolate, int index) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) + kIsolateRootsOffset;
-    return &reinterpret_cast<internal::Object**>(addr)[index];
+    return reinterpret_cast<internal::Object**>(addr + index * kApiPointerSize);
   }
 
   template <typename T>
   static inline T ReadField(Object* ptr, int offset) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(ptr) + offset - kHeapObjectTag;
     return *reinterpret_cast<T*>(addr);
   }
 
   static inline bool CanCastToHeapObject(void* o) { return false; }
   static inline bool CanCastToHeapObject(Context* o) { return true; }
@@ skipping 460 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_