Enable software decoding video with libvpx on Android

media/filters/vpx_video_decoder.cc

 // Copyright (c) 2012 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.
 
 #include "media/filters/vpx_video_decoder.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 274 matching lines @@
     delete context;
     return NULL;
   }
   return context;
 }
 
 bool VpxVideoDecoder::ConfigureDecoder(const VideoDecoderConfig& config) {
   if (config.codec() != kCodecVP8 && config.codec() != kCodecVP9)
     return false;
 
-  // In VP8 videos, only those with alpha are handled by VpxVideoDecoder. All
-  // other VP8 videos go to FFmpegVideoDecoder.
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
+  // When FFmpegVideoDecoder is available it handles VP8 that doesn't have
+  // alpha, and VpxVideoDecoder will handle VP8 with alpha.
   if (config.codec() == kCodecVP8 && config.format() != PIXEL_FORMAT_YV12A)
     return false;
+#endif
 
   CloseDecoder();
 
   vpx_codec_ = InitializeVpxContext(vpx_codec_, config);
   if (!vpx_codec_)
     return false;
 
   // We use our own buffers for VP9 so that there is no need to copy data after
   // decoding.
   if (config.codec() == kCodecVP9) {
@@ skipping 262 matching lines @@
         vpx_image->stride[VPX_PLANE_Y], vpx_image->d_h, video_frame->get());
     return;
   }
   CopyAPlane(vpx_image_alpha->planes[VPX_PLANE_Y],
              vpx_image_alpha->stride[VPX_PLANE_Y],
              vpx_image_alpha->d_h,
              video_frame->get());
 }
 
 }  // namespace media