Decouple MIDIAccess initialization from MIDIAccess class.

Source/web/MIDIClientProxy.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 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef MIDIClientProxy_h
 #define MIDIClientProxy_h
 
 #include "modules/webmidi/MIDIClient.h"
 #include "platform/heap/Handle.h"
 
 namespace WebCore {
-class MIDIAccess;
+class MIDIAccessInitializer;
 }
 
 namespace blink {
 
 class WebMIDIClient;
 
 class MIDIClientProxy FINAL : public WebCore::MIDIClient {
 public:
     static PassOwnPtr<MIDIClientProxy> create(WebMIDIClient* client)
     {
         return adoptPtr(new MIDIClientProxy(client));
     }
 
     // WebCore::MIDIClient
-    virtual void requestSysexPermission(PassRefPtrWillBeRawPtr<WebCore::MIDIAccess>) OVERRIDE;
-    virtual void cancelSysexPermissionRequest(WebCore::MIDIAccess*) OVERRIDE;
+    virtual void requestSysexPermission(WebCore::MIDIAccessInitializer*) OVERRIDE;
+    virtual void cancelSysexPermissionRequest(WebCore::MIDIAccessInitializer*) OVERRIDE;
 
 private:
     explicit MIDIClientProxy(WebMIDIClient*);
 
     WebMIDIClient* m_client;
 };
 
 } // namespace blink
 
 #endif // MIDIClientProxy_h