Add video decoding methods in Decryptor and add DecryptingVideoDecoder.

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 "media/base/filter_collection.h"
 #include "media/base/message_loop_factory.h"
+#include "media/crypto/decrypting_video_decoder.h"
 #include "media/filters/chunk_demuxer.h"
 #include "media/filters/dummy_demuxer.h"
 #include "media/filters/ffmpeg_audio_decoder.h"
 #include "media/filters/ffmpeg_demuxer.h"
 #include "media/filters/ffmpeg_video_decoder.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURL.h"
 #include "webkit/media/media_stream_client.h"
 
 namespace webkit_media {
 
 // Constructs and adds the default audio/video decoders to |filter_collection|.
 static void AddDefaultDecodersToCollection(
     media::MessageLoopFactory* message_loop_factory,
     media::FilterCollection* filter_collection,
     media::Decryptor* decryptor) {
   filter_collection->AddAudioDecoder(new media::FFmpegAudioDecoder(
       base::Bind(&media::MessageLoopFactory::GetMessageLoop,
                  base::Unretained(message_loop_factory),
                  media::MessageLoopFactory::kDecoder)));
 
+  scoped_refptr<media::DecryptingVideoDecoder> decrypting_video_decoder =
+      new media::DecryptingVideoDecoder(
+          base::Bind(&media::MessageLoopFactory::GetMessageLoop,
+                     base::Unretained(message_loop_factory),
+                     media::MessageLoopFactory::kDecoder),
+          decryptor);
+
   scoped_refptr<media::FFmpegVideoDecoder> ffmpeg_video_decoder =
       new media::FFmpegVideoDecoder(
           base::Bind(&media::MessageLoopFactory::GetMessageLoop,
                      base::Unretained(message_loop_factory),
                      media::MessageLoopFactory::kDecoder),
           decryptor);
+
+  filter_collection->GetVideoDecoders()->push_back(decrypting_video_decoder);

[ddorwin, 2012/09/21 00:36:08]

Does this order mean we will never decrypt with HW decoding enabled? I guess
there isn't much we can do until you address your comment below since the GVD is
provided outside this class

[xhwang, 2012/09/25 23:52:32]

Not in this CL. Will enable encrypt-only + GVD/FFVD later.

   filter_collection->GetVideoDecoders()->push_back(ffmpeg_video_decoder);

[xhwang, 2012/09/20 23:26:34]

After this change, we have 3 VideoDecoders in the list (in the following order):
GVD: only accepts unencrypted stream
DVD: only accepts encrypted stream (decrypt-and-decode)
FFVD: accepts both unencrypted and encrypted stream (decrypt-only).

In later CLs decrypt-only will be moved from FFVD to DVD.

[ddorwin, 2012/09/21 00:36:08]

It's not obvious here how the correct one will be selected, especially wrt
is_encrypted(). Probably worth an overall design comment somewhere.

[xhwang, 2012/09/25 23:52:32]

Added more comments for AddDecaultDecodersToCollection() to clarify this. Not
sure it's the best place for these comments though.

 }
 
 bool BuildMediaStreamCollection(const WebKit::WebURL& url,
                                 MediaStreamClient* client,
                                 media::MessageLoopFactory* message_loop_factory,
                                 media::FilterCollection* filter_collection) {
   if (!client)
     return false;
 
   scoped_refptr<media::VideoDecoder> video_decoder = client->GetVideoDecoder(
@@ skipping 31 matching lines @@
   filter_collection->SetDemuxer(new media::FFmpegDemuxer(
       message_loop_factory->GetMessageLoop(
           media::MessageLoopFactory::kPipeline),
       data_source));
 
   AddDefaultDecodersToCollection(message_loop_factory, filter_collection,
                                  decryptor);
 }
 
 }  // webkit_media