Reland 8636: Implement setting the length property for FixedDoubleArrays.

src/objects.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 2151 matching lines @@
   inline void set_the_hole(int index);
 
   // Checking for the hole.
   inline bool is_the_hole(int index);
 
   // Garbage collection support.
   inline static int SizeFor(int length) {
     return kHeaderSize + length * kDoubleSize;
   }
 
+  // Code Generation support.
+  static int OffsetOfElementAt(int index) { return SizeFor(index); }
+
   inline static bool is_the_hole_nan(double value);
   inline static double hole_nan_as_double();
   inline static double canonical_not_the_hole_nan_as_double();
 
   // Casting.
   static inline FixedDoubleArray* cast(Object* obj);
 
   // Maximal allowed size, in bytes, of a single FixedDoubleArray.
   // Prevents overflowing size computations, as well as extreme memory
   // consumption.
@@ skipping 4989 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_