Cast: Adding support for GPU accelerated encode

media/cast/video_sender/video_sender.gypi

 # Copyright 2013 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.
 
 {
   'includes': [
     'codecs/vp8/vp8_encoder.gypi',
   ],
   'targets': [
     {
       'target_name': 'video_sender',
       'type': 'static_library',
       'include_dirs': [
          '<(DEPTH)/',
          '<(DEPTH)/third_party/',
       ],
       'sources': [
+        'external_video_encoder.h',
+        'external_video_encoder.cc',
         'video_encoder.h',
-        'video_encoder.cc',
+        'video_encoder_impl.h',
+        'video_encoder_impl.cc',
         'video_sender.h',
         'video_sender.cc',
       ], # source
       'dependencies': [
         '<(DEPTH)/crypto/crypto.gyp:crypto',
         '<(DEPTH)/media/cast/rtcp/rtcp.gyp:*',
         '<(DEPTH)/media/cast/rtp_sender/rtp_sender.gyp:*',
         '<(DEPTH)/media/media.gyp:media',
         '<(DEPTH)/media/media.gyp:shared_memory_support',
         'congestion_control',
         'cast_vp8_encoder',
       ],
     },
   ],
 }