Handled return-value of SetElement in some cases, or avoided it in other.

src/objects.h

 // Copyright 2010 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 1497 matching lines @@
   inline Object* GetPrototype();
 
   // Set the object's prototype (only JSObject and null are allowed).
   MUST_USE_RESULT MaybeObject* SetPrototype(Object* value,
                                             bool skip_hidden_prototypes);
 
   // Tells whether the index'th element is present.
   inline bool HasElement(uint32_t index);
   bool HasElementWithReceiver(JSObject* receiver, uint32_t index);
 
+  // Computes the new capacity when expanding the elements of a JSObject.
+  static int NewElementsCapacity(int old_capacity) {
+    // (old_capacity + 50%) + 16
+    return old_capacity + (old_capacity >> 1) + 16;
+  }
+
   // Tells whether the index'th element is present and how it is stored.
   enum LocalElementType {
     // There is no element with given index.
     UNDEFINED_ELEMENT,
 
     // Element with given index is handled by interceptor.
     INTERCEPTED_ELEMENT,
 
     // Element with given index is character in string.
     STRING_CHARACTER_ELEMENT,
@@ skipping 5034 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_