Update VideoFramePump to pass un-changed frames to encoders.

remoting/codec/codec_test.h

 // Copyright (c) 2012 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_CODEC_TEST_H_
 #define REMOTING_CODEC_CODEC_TEST_H_
 
 #include <list>
 
 #include "base/memory/ref_counted.h"
 
 namespace webrtc {
 class DesktopFrame;
 class DesktopSize;
 }
 
 namespace remoting {
 
 class VideoDecoder;
 class VideoEncoder;
 
 // Generate test data and test the encoder for a regular encoding sequence.
 // This will test encoder test and the sequence of messages sent.
 //
 // If |strict| is set to true then this routine will make sure the updated
 // rects match dirty rects.
 void TestVideoEncoder(VideoEncoder* encoder, bool strict);
 
+// Generate test data and test the encoder for a sequence of one "changed"
+// frame followed by one or more "unchanged" frames, and verify that the
+// encoder sends up to |max_topoff_frames| of non-empty data for unchanged
+// frames, but eventually returns no data.
+void TestVideoEncoderEmptyFrames(VideoEncoder* encoder, int max_topoff_frames);
+
 // Generate test data and test the encoder and decoder pair.
 //
 // If |strict| is set to true, this routine will make sure the updated rects
 // are correct.
 void TestVideoEncoderDecoder(VideoEncoder* encoder,
                              VideoDecoder* decoder,
                              bool strict);
 
 // Generate a frame containing a gradient, and test the encoder and decoder
 // pair.
@@ skipping 10 matching lines @@
 // supply any frames then a single full-frame of randomized pixels is used.
 float MeasureVideoEncoderFpsWithSize(VideoEncoder* encoder,
                                      const webrtc::DesktopSize& size);
 float MeasureVideoEncoderFpsWithFrames(
     VideoEncoder* encoder,
     const std::list<webrtc::DesktopFrame*>& frames);
 
 }  // namespace remoting
 
 #endif  // REMOTING_CODEC_CODEC_TEST_H_