Update Bind to match its comments and always capture by value.

talk/media/webrtc/webrtcvideocapturer.h

Index: talk/media/webrtc/webrtcvideocapturer.h
diff --git a/talk/media/webrtc/webrtcvideocapturer.h b/talk/media/webrtc/webrtcvideocapturer.h
index 66991e097fde473945580eb31528b83105a2ddda..0a99884fe10619f38dceded7194523875dfb69f7 100644
--- a/talk/media/webrtc/webrtcvideocapturer.h
+++ b/talk/media/webrtc/webrtcvideocapturer.h
@@ -92,7 +92,7 @@ class WebRtcVideoCapturer : public VideoCapturer,
   // directly from OnIncomingCapturedFrame.
   // TODO(tommi): Remove this workaround when we've updated the WebRTC capturers
   // to follow the same contract.
-  void SignalFrameCapturedOnStartThread(const webrtc::VideoFrame frame);
+  void SignalFrameCapturedOnStartThread(const webrtc::VideoFrame& frame);
 
   rtc::scoped_ptr<WebRtcVcmFactoryInterface> factory_;
   webrtc::VideoCaptureModule* module_;