Decouple MIDIAccess initialization from MIDIAccess class.

Source/modules/webmidi/MIDIClient.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * 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
@@ skipping 18 matching lines @@
  */
 
 #ifndef MIDIClient_h
 #define MIDIClient_h
 
 #include "platform/heap/Handle.h"
 
 namespace WebCore {
 
 class LocalFrame;
-class MIDIAccess;
+class MIDIAccessInitializer;
 
 class MIDIClient {
 public:
-    virtual void requestSysexPermission(PassRefPtrWillBeRawPtr<MIDIAccess>) = 0;
-    virtual void cancelSysexPermissionRequest(MIDIAccess*) = 0;
+    virtual void requestSysexPermission(MIDIAccessInitializer*) = 0;
+    virtual void cancelSysexPermissionRequest(MIDIAccessInitializer*) = 0;
 
     virtual ~MIDIClient() { }
 };
 
 void provideMIDITo(LocalFrame&, PassOwnPtr<MIDIClient>);
 
 } // namespace WebCore
 
 #endif // MIDIClient_h