VideoCaptureImpl: Remove unused member variable |_capture_encoded_frame|

The end goal except cleanup is to remove webrtc::VideoFrame.

R=mflodman@webrtc.org, pbos@webrtc.org, perkj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/37219004

Cr-Commit-Position: refs/heads/master@{#8388}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8388 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/video_capture/video_capture_impl.h b/webrtc/modules/video_capture/video_capture_impl.h
index 1ec13c8..01493bc 100644
--- a/webrtc/modules/video_capture/video_capture_impl.h
+++ b/webrtc/modules/video_capture/video_capture_impl.h
@@ -135,7 +135,6 @@
     VideoRotationMode _rotateFrame; //Set if the frame should be rotated by the capture module.
 
     I420VideoFrame _captureFrame;
-    VideoFrame _capture_encoded_frame;
 
     // Used to make sure incoming timestamp is increasing for every frame.
     int64_t last_capture_time_;