media: Add support for playback of VP8 Alpha video streams

webkit/media/webmediaplayer_impl.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 "webkit/media/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 #include <vector>
@@ skipping 1285 matching lines @@
   filter_collection->SetAudioRenderer(audio_renderer.Pass());
 
   // Create our video decoders and renderer.
   ScopedVector<media::VideoDecoder> video_decoders;
 
   if (gpu_factories_) {
     video_decoders.push_back(new media::GpuVideoDecoder(
         media_thread_.message_loop_proxy(), gpu_factories_));
   }
 
-  video_decoders.push_back(new media::FFmpegVideoDecoder(
-      media_thread_.message_loop_proxy()));
-
   // TODO(phajdan.jr): Remove ifdefs when libvpx with vp9 support is released
   // (http://crbug.com/174287) .
 #if !defined(MEDIA_DISABLE_LIBVPX)
-  if (cmd_line->HasSwitch(switches::kEnableVp9Playback)) {
+  if (cmd_line->HasSwitch(switches::kEnableVp9Playback) ||
+      cmd_line->HasSwitch(switches::kEnableVp8AlphaPlayback)) {
     video_decoders.push_back(new media::VpxVideoDecoder(
         media_thread_.message_loop_proxy()));
   }
 #endif  // !defined(MEDIA_DISABLE_LIBVPX)
 
+  video_decoders.push_back(new media::FFmpegVideoDecoder(
+      media_thread_.message_loop_proxy()));
+
   scoped_ptr<media::VideoRenderer> video_renderer(
       new media::VideoRendererBase(
           media_thread_.message_loop_proxy(),
           video_decoders.Pass(),
           set_decryptor_ready_cb,
           base::Bind(&WebMediaPlayerImpl::FrameReady, base::Unretained(this)),
           BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::SetOpaque),
           true));
   filter_collection->SetVideoRenderer(video_renderer.Pass());
 
   return filter_collection.Pass();
 }
 
 }  // namespace webkit_media