Add a ref-counted data holder to ArrayBufferContents

Source/wtf/ArrayBuffer.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 #include "config.h"
 #include "wtf/ArrayBuffer.h"
 
 #include "wtf/ArrayBufferView.h"
 #include "wtf/RefPtr.h"
 
 namespace WTF {
 
 bool ArrayBuffer::transfer(ArrayBufferContents& result)
 {
+    ASSERT(!isShared());
     RefPtr<ArrayBuffer> keepAlive(this);
 
     if (!m_contents.data()) {
-        result.clear();
+        result.neuter();
         return false;
     }
 
     bool allViewsAreNeuterable = true;
     for (ArrayBufferView* i = m_firstView; i; i = i->m_nextView) {
         if (!i->isNeuterable())
             allViewsAreNeuterable = false;
     }
 
     if (allViewsAreNeuterable) {
         m_contents.transfer(result);
     } else {
         m_contents.copyTo(result);
         if (!result.data())
             return false;
     }
 
     while (m_firstView) {
         ArrayBufferView* current = m_firstView;
         removeView(current);
         if (allViewsAreNeuterable || current->isNeuterable())
             current->neuter();
     }
 
     m_isNeutered = true;
 
     return true;
 }
 
+bool ArrayBuffer::shareContentsWith(ArrayBufferContents& result)
+{
+    ASSERT(isShared());
+    RefPtr<ArrayBuffer> keepAlive(this);
+
+    if (!m_contents.data()) {
+        result.neuter();
+        return false;
+    }
+
+    m_contents.shareWith(result);
+    return true;
+}
+
 void ArrayBuffer::addView(ArrayBufferView* view)
 {
     view->m_buffer = this;
     view->m_prevView = 0;
     view->m_nextView = m_firstView;
     if (m_firstView)
         m_firstView->m_prevView = view;
     m_firstView = view;
 }
 
 void ArrayBuffer::removeView(ArrayBufferView* view)
 {
     ASSERT(this == view->m_buffer);
     if (view->m_nextView)
         view->m_nextView->m_prevView = view->m_prevView;
     if (view->m_prevView)
         view->m_prevView->m_nextView = view->m_nextView;
     if (m_firstView == view)
         m_firstView = view->m_nextView;
     view->m_prevView = view->m_nextView = 0;
 }
 
 }