Fix C++ type of Factory::NewFixedDoubleArray.

src/builtins.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 452 matching lines @@
     // we should never hit this case.
     ASSERT(to_add <= (Smi::kMaxValue - len));
 
     int new_length = len + to_add;
 
     Handle<FixedDoubleArray> new_elms;
 
     if (new_length > elms_len) {
       // New backing storage is needed.
       int capacity = new_length + (new_length >> 1) + 16;
-      new_elms = isolate->factory()->NewFixedDoubleArray(capacity);
+      // Create new backing store; since capacity > 0, we can
+      // safely cast to FixedDoubleArray.
+      new_elms = Handle<FixedDoubleArray>::cast(
+          isolate->factory()->NewFixedDoubleArray(capacity));
 
       ElementsAccessor* accessor = array->GetElementsAccessor();
       accessor->CopyElements(
           elms_obj, 0, kind, new_elms, 0,
           ElementsAccessor::kCopyToEndAndInitializeToHole);
 
     } else {
       // to_add is > 0 and new_length <= elms_len, so elms_obj cannot be the
       // empty_fixed_array.
       new_elms = Handle<FixedDoubleArray>::cast(elms_obj);
@@ skipping 1250 matching lines @@
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal