media: Add support for playback of VP8 Alpha video streams

webkit/media/filter_helpers.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/filter_helpers.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "media/base/filter_collection.h"
 #include "media/base/media_switches.h"
@@ skipping 23 matching lines @@
       new media::FFmpegAudioDecoder(message_loop);
   filter_collection->GetAudioDecoders()->push_back(ffmpeg_audio_decoder);
 
   const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
   if (cmd_line->HasSwitch(switches::kEnableOpusPlayback)) {
     scoped_refptr<media::OpusAudioDecoder> opus_audio_decoder =
         new media::OpusAudioDecoder(message_loop);
     filter_collection->GetAudioDecoders()->push_back(opus_audio_decoder);
   }
 
+  if (cmd_line->HasSwitch(switches::kEnableVp9Playback) ||
+      cmd_line->HasSwitch(switches::kEnableVp8AlphaPlayback)) {
+    scoped_refptr<media::VpxVideoDecoder> vpx_video_decoder =
+        new media::VpxVideoDecoder(message_loop);
+    filter_collection->GetVideoDecoders()->push_back(vpx_video_decoder);
+  }
+
   scoped_refptr<media::FFmpegVideoDecoder> ffmpeg_video_decoder =
       new media::FFmpegVideoDecoder(message_loop);
   filter_collection->GetVideoDecoders()->push_back(ffmpeg_video_decoder);
 
-  if (cmd_line->HasSwitch(switches::kEnableVp9Playback)) {
-    scoped_refptr<media::VpxVideoDecoder> vpx_video_decoder =
-        new media::VpxVideoDecoder(message_loop);
-    filter_collection->GetVideoDecoders()->push_back(vpx_video_decoder);
-  }
 }
 
 bool BuildMediaStreamCollection(
     const WebKit::WebURL& url,
     MediaStreamClient* client,
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     media::FilterCollection* filter_collection) {
   if (!client)
     return false;
 
@@ skipping 32 matching lines @@
     const scoped_refptr<media::DataSource>& data_source,
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     media::FilterCollection* filter_collection) {
   filter_collection->SetDemuxer(new media::FFmpegDemuxer(
       message_loop, data_source));
 
   AddDefaultDecodersToCollection(message_loop, filter_collection);
 }
 
 }  // webkit_media