MediaCaptureFromElement: add support for audio captureStream().

third_party/WebKit/public/platform/Platform.h

 /*
  * Copyright (C) 2012 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 513 matching lines @@
     virtual WebRTCCertificateGenerator* createRTCCertificateGenerator() { return nullptr; }
 
     // May return null if WebRTC functionality is not available or out of resources.
     virtual WebMediaStreamCenter* createMediaStreamCenter(WebMediaStreamCenterClient*) { return nullptr; }
 
     // Creates a WebCanvasCaptureHandler to capture Canvas output.
     virtual WebCanvasCaptureHandler* createCanvasCaptureHandler(const WebSize&, double, WebMediaStreamTrack*) { return nullptr; }
 
     // Fills in the WebMediaStream to capture from the WebMediaPlayer identified
     // by the second parameter.
-    virtual void createHTMLVideoElementCapturer(WebMediaStream*, WebMediaPlayer*) {}
+    virtual void createHTMLVideoElementCapturer(WebMediaStream*, WebMediaPlayer*) { }
+    virtual void createHTMLAudioElementCapturer(WebMediaStream*, WebMediaPlayer*) { }
 
     // Creates a WebImageCaptureFrameGrabber to take a snapshot of a Video Tracks.
     // May return null if the functionality is not available.
     virtual WebImageCaptureFrameGrabber* createImageCaptureFrameGrabber() { return nullptr; }
 
     // WebWorker ----------------------------------------------------------
 
     virtual void didStartWorkerThread() { }
     virtual void willStopWorkerThread() { }
     virtual void workerContextCreated(const v8::Local<v8::Context>& worker) { }
@@ skipping 90 matching lines @@
 protected:
     Platform();
     virtual ~Platform() { }
 
     WebThread* m_mainThread;
 };
 
 } // namespace blink
 
 #endif