Refactor + enable GN check on video_coding_utility

webrtc/modules/video_coding/utility/qp_parser.cc

-/*
- *  Copyright (c) 2015 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.
- */
-
-#include "webrtc/modules/video_coding/utility/qp_parser.h"
-
-#include "webrtc/common_types.h"
-#include "webrtc/modules/video_coding/utility/vp8_header_parser.h"
-
-namespace webrtc {
-
-bool QpParser::GetQp(const VCMEncodedFrame& frame, int* qp) {
-  switch (frame.CodecSpecific()->codecType) {
-    case kVideoCodecVP8:
-      // QP range: [0, 127].
-      return vp8::GetQp(frame.Buffer(), frame.Length(), qp);
-    default:
-      return false;
-  }
-}
-
-}  // namespace webrtc