Update VideoFramePump to pass un-changed frames to encoders.

remoting/codec/video_encoder_verbatim_unittest.cc

Index: remoting/codec/video_encoder_verbatim_unittest.cc
diff --git a/remoting/codec/video_encoder_verbatim_unittest.cc b/remoting/codec/video_encoder_verbatim_unittest.cc
index b9e72ac1ec120b74b679bcb7820ad09238e86248..a294d7bdd5cbfb8b15d711482b8c76e6fdebb131 100644
--- a/remoting/codec/video_encoder_verbatim_unittest.cc
+++ b/remoting/codec/video_encoder_verbatim_unittest.cc
@@ -21,4 +21,9 @@ TEST(VideoEncoderVerbatimTest, EncodeAndDecode) {
   TestVideoEncoderDecoder(encoder.get(), decoder.get(), true);
 }
 
+TEST(VideoEncoderVerbatimTest, EncodeUnchangedFrame) {
+  scoped_ptr<VideoEncoderVerbatim> encoder(new VideoEncoderVerbatim());
+  TestVideoEncoderEmptyFrames(encoder.get(), 0);
+}
+
 }  // namespace remoting