Sync the getComputedStyle() IDL with the spec

Source/core/frame/LocalDOMWindow.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 115 matching lines @@
     int orientation() const override;
     Console* console() const override;
     Performance* performance() const override;
     DOMWindowCSS* css() const override;
     DOMSelection* getSelection() override;
     void focus(ExecutionContext* = 0) override;
     void blur() override;
     void close(ExecutionContext* = 0) override;
     void print() override;
     void stop() override;
-    void alert(const String& message = String()) override;
+    void alert(const String& message) override;

[arv (Not doing code reviews), 2014/12/01 14:20:09]

This looks unrelated

[philipj_slow, 2014/12/01 20:48:54]

Yeah, I forgot to say why in the description. The default argument String() for
alert() and getComputedStyle() aren't needed in the override because they aren't
omitted internally and also aren't part of the signature, so a different default
would still compile, I think. I've reverted the change and left alert() and
getComputedStyle() inconsistent on this point, let me know if you want me to
make it consistent and in which direction.

     bool confirm(const String& message) override;
     String prompt(const String& message, const String& defaultValue) override;
     bool find(const String&, bool caseSensitive, bool backwards, bool wrap, bool wholeWord, bool searchInFrames, bool showDialog) const override;
 
     // FIXME: ScrollBehaviorSmooth is currently unsupported in PinchViewport.
     // crbug.com/434497
     void scrollBy(double x, double y, ScrollBehavior = ScrollBehaviorAuto) const override;
     void scrollBy(double x, double y, const ScrollOptions&, ExceptionState&) const override;
     void scrollTo(double x, double y, ScrollBehavior = ScrollBehaviorAuto) const override;
     void scrollTo(double x, double y, const ScrollOptions&, ExceptionState&) const override;
@@ skipping 194 matching lines @@
 }
 
 inline String LocalDOMWindow::defaultStatus() const
 {
     return m_defaultStatus;
 }
 
 } // namespace blink
 
 #endif // LocalDOMWindow_h