passing |buffer| by reference in AndroidVideoCapturer::OnIncomingFrame

talk/app/webrtc/androidvideocapturer.h

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * 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 notice,
@@ skipping 49 matching lines @@
  public:
   explicit AndroidVideoCapturer(
       const rtc::scoped_refptr<AndroidVideoCapturerDelegate>& delegate);
   virtual ~AndroidVideoCapturer();
 
   // Called from JNI when the capturer has been started.
   void OnCapturerStarted(bool success);
 
   // Called from JNI when a new frame has been captured.
   // Argument |buffer| is intentionally by value, for use with rtc::Bind.
-  void OnIncomingFrame(rtc::scoped_refptr<webrtc::VideoFrameBuffer> buffer,
-                       int rotation,
-                       int64_t time_stamp);
+  void OnIncomingFrame(
+      const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
+      int rotation,
+      int64_t time_stamp);
 
   // Called from JNI to request a new video format.
   void OnOutputFormatRequest(int width, int height, int fps);
 
   AndroidVideoCapturerDelegate* delegate() { return delegate_.get(); }
 
   // cricket::VideoCapturer implementation.
   bool GetBestCaptureFormat(const cricket::VideoFormat& desired,
                             cricket::VideoFormat* best_format) override;
 
@@ skipping 15 matching lines @@
 
   class FrameFactory;
   FrameFactory* frame_factory_;  // Owned by cricket::VideoCapturer.
 
   cricket::CaptureState current_state_;
 };
 
 }  // namespace webrtc
 
 #endif  // TALK_APP_WEBRTC_ANDROIDVIDEOCAPTURER_H_