Update VideoFramePump to pass un-changed frames to encoders.

remoting/codec/video_encoder_vpx.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_CODEC_VIDEO_ENCODER_VPX_H_
 #define REMOTING_CODEC_VIDEO_ENCODER_VPX_H_
 
 #include "base/callback.h"
 #include "base/time/time.h"
 #include "remoting/codec/scoped_vpx_codec.h"
@@ skipping 40 matching lines @@
 
   // Adds areas changed in the most recent frame to |updated_region|. This
   // includes both content changes and areas enhanced by cyclic refresh.
   void UpdateRegionFromActiveMap(webrtc::DesktopRegion* updated_region);
 
   // True if the encoder is for VP9, false for VP8.
   const bool use_vp9_;
 
   // Options controlling VP9 encode quantization and color space.
   // These are always off (false) for VP8.
-  bool lossless_encode_;
-  bool lossless_color_;
+  bool lossless_encode_ = false;
+  bool lossless_color_ = false;
 
   // Holds the initialized & configured codec.
   ScopedVpxCodec codec_;
 
   // Used to generate zero-based frame timestamps.
   base::TimeTicks timestamp_base_;
 
   // VPX image and buffer to hold the actual YUV planes.
   scoped_ptr<vpx_image_t> image_;
   scoped_ptr<uint8[]> image_buffer_;
 
   // Active map used to optimize out processing of un-changed macroblocks.
   scoped_ptr<uint8[]> active_map_;
-  int active_map_width_;
-  int active_map_height_;
+  int active_map_width_ = 0;
+  int active_map_height_ = 0;
+
+  // Number of "top-off" frames we've encoded since we were last passed a
+  // frame containing an actual change. Used only when encoding with top-off.
+  int topoff_frame_count_ = 0;
 
   // Used to help initialize VideoPackets from DesktopFrames.
   VideoEncoderHelper helper_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoEncoderVpx);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CODEC_VIDEO_ENCODER_VP8_H_