Replace SetCapturer and SetCaptureDevice by SetSource.

webrtc/api/videocapturertracksource.h

Index: webrtc/api/videocapturertracksource.h
diff --git a/webrtc/api/videocapturertracksource.h b/webrtc/api/videocapturertracksource.h
index 96f8bffc23a652e34b7808b326272a12f211a649..2eb7b507418799e17accd6049ca76bf824cf19f0 100644
--- a/webrtc/api/videocapturertracksource.h
+++ b/webrtc/api/videocapturertracksource.h
@@ -47,10 +47,6 @@ class VideoCapturerTrackSource : public VideoTrackSource,
       cricket::VideoCapturer* capturer,
       bool remote);
 
-  cricket::VideoCapturer* GetVideoCapturer() override {
-    return video_capturer_.get();
-  }
-
   bool is_screencast() const override {
     return video_capturer_->IsScreencast();
   }