Move VideoDecoder::Create() logic to separate internal video decoder factory

webrtc/video/BUILD.gn

 # Copyright (c) 2014 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.
 
 import("../build/webrtc.gni")
 
@@ skipping 18 matching lines @@
     "send_delay_stats.cc",
     "send_delay_stats.h",
     "send_statistics_proxy.cc",
     "send_statistics_proxy.h",
     "stats_counter.cc",
     "stats_counter.h",
     "stream_synchronization.cc",
     "stream_synchronization.h",
     "transport_adapter.cc",
     "transport_adapter.h",
-    "video_decoder.cc",
     "video_receive_stream.cc",
     "video_receive_stream.h",
     "video_send_stream.cc",
     "video_send_stream.h",
     "video_stream_decoder.cc",
     "video_stream_decoder.h",
     "vie_encoder.cc",
     "vie_encoder.h",
     "vie_remb.cc",
     "vie_remb.h",
@@ skipping 115 matching lines @@
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
     if (rtc_use_h264) {
       defines = [ "WEBRTC_USE_H264" ]
     }
   }
 }