Delete I420 encoder and decoder.

webrtc/modules/video_coding/video_coding.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'webrtc_video_coding',
       'type': 'static_library',
       'dependencies': [
         'webrtc_h264',
-        'webrtc_i420',
         '<(webrtc_root)/common_video/common_video.gyp:common_video',
         '<(webrtc_root)/modules/video_coding/utility/video_coding_utility.gyp:video_coding_utility',
         '<(webrtc_root)/system_wrappers/system_wrappers.gyp:system_wrappers',
         '<(webrtc_vp8_dir)/vp8.gyp:webrtc_vp8',
         '<(webrtc_vp9_dir)/vp9.gyp:webrtc_vp9',
       ],
       'sources': [
         # interfaces
         'include/bitrate_adjuster.h',
         'include/video_coding.h',
@@ skipping 61 matching lines @@
         'timing.cc',
         'video_coding_impl.cc',
         'video_sender.cc',
         'video_receiver.cc',
       ], # source
       # TODO(jschuh): Bug 1348: fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }