Move btoa() / atob() implementation out of DOMWindow

Source/core/page/DOMWindow.h

Index: Source/core/page/DOMWindow.h
diff --git a/Source/core/page/DOMWindow.h b/Source/core/page/DOMWindow.h
index ac289d4d1c526f106151321bf4938d12c5ed98e8..f22cd87fc0a3fff2013a27cbc674c7ca5d92b27c 100644
--- a/Source/core/page/DOMWindow.h
+++ b/Source/core/page/DOMWindow.h
@@ -29,6 +29,7 @@
 
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/dom/EventTarget.h"
+#include "core/page/DOMWindowBase64.h"
 #include "core/page/FrameDestructionObserver.h"
 #include "core/platform/Supplementable.h"
 
@@ -87,7 +88,7 @@ namespace WebCore {
 
     enum SetLocationLocking { LockHistoryBasedOnGestureState, LockHistoryAndBackForwardList };
 
-    class DOMWindow : public RefCounted<DOMWindow>, public ScriptWrappable, public EventTarget, public FrameDestructionObserver, public Supplementable<DOMWindow> {
+    class DOMWindow : public RefCounted<DOMWindow>, public ScriptWrappable, public EventTarget, public FrameDestructionObserver, public DOMWindowBase64, public Supplementable<DOMWindow> {

[abarth-chromium, 2013/07/18 08:17:14]

Why do we need to subclass?  Can't we just use a partial interface and make
these static functions?

     public:
         static PassRefPtr<DOMWindow> create(Frame* frame) { return adoptRef(new DOMWindow(frame)); }
         virtual ~DOMWindow();
@@ -159,8 +160,6 @@ namespace WebCore {
         void alert(const String& message);
         bool confirm(const String& message);
         String prompt(const String& message, const String& defaultValue);
-        String btoa(const String& stringToEncode, ExceptionCode&);
-        String atob(const String& encodedString, ExceptionCode&);
 
         bool find(const String&, bool caseSensitive, bool backwards, bool wrap, bool wholeWord, bool searchInFrames, bool showDialog) const;