Revert of Move MutableDataY{,U,V} methods to I420Buffer only.

webrtc/modules/video_processing/test/video_processing_unittest.h

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 15 matching lines @@
   virtual void SetUp();
   virtual void TearDown();
   static void SetUpTestCase() {
     Trace::CreateTrace();
     std::string trace_file = webrtc::test::OutputPath() + "VPMTrace.txt";
     ASSERT_EQ(0, Trace::SetTraceFile(trace_file.c_str()));
   }
   static void TearDownTestCase() { Trace::ReturnTrace(); }
   VideoProcessing* vp_;
   FILE* source_file_;
+  VideoFrame video_frame_;
   const int width_;
   const int half_width_;
   const int height_;
   const int size_y_;
   const int size_uv_;
   const size_t frame_length_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_PROCESSING_TEST_VIDEO_PROCESSING_UNITTEST_H_