[Chromoting] Add a unit test to verify that the VP8 codec doesn't change color values too much.

remoting/base/decoder_vp8_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 "media/base/video_frame.h"
 #include "remoting/base/codec_test.h"
 #include "remoting/base/decoder_vp8.h"
 #include "remoting/base/encoder_vp8.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace remoting {
 
 TEST(DecoderVp8Test, EncodeAndDecode) {
   EncoderVp8 encoder;
   DecoderVp8 decoder;
   TestEncoderDecoder(&encoder, &decoder, false);
 }
 
+// Check that encoding and decoding a particular frame doesn't change the
+// frame too much. The frame used is a gradient, which does not contain sharp
+// transitions, so encoding lossiness should not be too high.
+TEST(DecoderVp8Test, Gradient) {
+  EncoderVp8 encoder;
+  DecoderVp8 decoder;
+  TestEncoderDecoderGradient(&encoder, &decoder, 0.03, 0.01);
+}
+
 }  // namespace remoting