Reland 8636: Implement setting the length property for FixedDoubleArrays.

src/objects-inl.h

 // Copyright 2011 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 3989 matching lines @@
   return map()->has_named_interceptor();
 }
 
 
 bool JSObject::HasIndexedInterceptor() {
   return map()->has_indexed_interceptor();
 }
 
 
 bool JSObject::AllowsSetElementsLength() {
-  bool result = elements()->IsFixedArray();
+  bool result = elements()->IsFixedArray() ||
+      elements()->IsFixedDoubleArray();
   ASSERT(result == !HasExternalArrayElements());
   return result;
 }
 
 
 MaybeObject* JSObject::EnsureWritableFastElements() {
   ASSERT(HasFastElements());
   FixedArray* elems = FixedArray::cast(elements());
   Isolate* isolate = GetIsolate();
   if (elems->map() != isolate->heap()->fixed_cow_array_map()) return elems;
@@ skipping 459 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_