Update VideoFramePump to pass un-changed frames to encoders.

remoting/codec/video_encoder_verbatim_unittest.cc

 // Copyright (c) 2010 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.
 
 #include "remoting/codec/video_encoder_verbatim.h"
 
 #include "remoting/codec/codec_test.h"
 #include "remoting/codec/video_decoder_verbatim.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace remoting {
 
 TEST(VideoEncoderVerbatimTest, TestVideoEncoder) {
   scoped_ptr<VideoEncoderVerbatim> encoder(new VideoEncoderVerbatim());
   TestVideoEncoder(encoder.get(), true);
 }
 
 TEST(VideoEncoderVerbatimTest, EncodeAndDecode) {
   scoped_ptr<VideoEncoderVerbatim> encoder(new VideoEncoderVerbatim());
   scoped_ptr<VideoDecoderVerbatim> decoder(new VideoDecoderVerbatim());
   TestVideoEncoderDecoder(encoder.get(), decoder.get(), true);
 }
 
+TEST(VideoEncoderVerbatimTest, EncodeUnchangedFrame) {
+  scoped_ptr<VideoEncoderVerbatim> encoder(new VideoEncoderVerbatim());
+  TestVideoEncoderEmptyFrames(encoder.get(), 0);
+}
+
 }  // namespace remoting