Split "Online" and "Offline" AudioContext processing

Source/modules/webaudio/AudioSourceNode.h

 /*
  * Copyright (C) 2010 Google 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
@@ skipping 15 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef AudioSourceNode_h
 #define AudioSourceNode_h
 
 #include "modules/webaudio/AudioNode.h"
 
 namespace blink {
 
+class AbstractAudioContext;
+
 class AudioSourceNode : public AudioNode {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    AudioSourceNode(AudioContext& context)
+    AudioSourceNode(AbstractAudioContext& context)
         : AudioNode(context) { }
 };
 
 } // namespace blink
 
 #endif // AudioSourceNode_h