Move video_encoder.h and video_decoder.h to /api and create GN targets for them

webrtc/video/vie_encoder.h

 /*
  *  Copyright (c) 2012 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.
  */
 
 #ifndef WEBRTC_VIDEO_VIE_ENCODER_H_
 #define WEBRTC_VIDEO_VIE_ENCODER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "webrtc/api/video/video_rotation.h"
+#include "webrtc/api/video_codecs/video_encoder.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/event.h"
 #include "webrtc/base/sequenced_task_checker.h"
 #include "webrtc/base/task_queue.h"
 #include "webrtc/call/call.h"
 #include "webrtc/common_types.h"
 #include "webrtc/common_video/include/video_bitrate_allocator.h"
 #include "webrtc/media/base/videosinkinterface.h"
 #include "webrtc/modules/video_coding/include/video_coding_defines.h"
 #include "webrtc/modules/video_coding/utility/quality_scaler.h"
 #include "webrtc/modules/video_coding/video_coding_impl.h"
 #include "webrtc/system_wrappers/include/atomic32.h"
 #include "webrtc/typedefs.h"
 #include "webrtc/video/overuse_frame_detector.h"
-#include "webrtc/video_encoder.h"
 #include "webrtc/video_send_stream.h"
 
 namespace webrtc {
 
 class ProcessThread;
 class SendStatisticsProxy;
 class VideoBitrateAllocationObserver;
 
 // VieEncoder represent a video encoder that accepts raw video frames as input
 // and produces an encoded bit stream.
@@ skipping 201 matching lines @@
   // All public methods are proxied to |encoder_queue_|. It must must be
   // destroyed first to make sure no tasks are run that use other members.
   rtc::TaskQueue encoder_queue_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(ViEEncoder);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_VIE_ENCODER_H_