Add support for encrypted WebM files as defined in the RFC.

webkit/media/filter_helpers.h

 // 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.
 
 #ifndef WEBKIT_MEDIA_FILTER_HELPERS_H_
 #define WEBKIT_MEDIA_FILTER_HELPERS_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 
 namespace media {
-class AesDecryptor;
+class Decryptor;
 class ChunkDemuxerClient;
 class DataSource;
 class FFmpegVideoDecoder;
 class FilterCollection;
 class MessageLoopFactory;
 }
 
 namespace WebKit {
 class WebURL;
 }
@@ skipping 14 matching lines @@
 // Builds the required filters for handling media source URLs, adds them to
 // |filter_collection| and fills |video_decoder| returning true if successful.
 //
 // |filter_collection| is not modified if this method returns false.
 bool BuildMediaSourceCollection(
     const WebKit::WebURL& url,
     const WebKit::WebURL& media_source_url,
     media::ChunkDemuxerClient* client,
     media::MessageLoopFactory* message_loop_factory,
     media::FilterCollection* filter_collection,
-    media::AesDecryptor* decryptor,
+    media::Decryptor* decryptor,

[xhwang, 2012/06/14 19:42:27]

We can keep the use of AesDecryptor (HmacAesDecryptor after renaming) as is if
we don't add a new Decryptor (see other comment about this).

FYI, I am also working on a CL that defines the Decryptor interface and replaces
AesDecryptor with Decryptor in many decryptor access points:

http://codereview.chromium.org/10539150/

I didn't do this earlier because in media stack code, if we only have one
implementation, then we don't play the interface-implementation game. I am doing
this now because we'll have a CdmDecryptor very soon.

     scoped_refptr<media::FFmpegVideoDecoder>* video_decoder);
 
 // Builds the required filters for handling regular URLs and adds them to
 // |filter_collection| and fills |video_decoder| returning true if successful.
 void BuildDefaultCollection(
     const scoped_refptr<media::DataSource>& data_source,
     media::MessageLoopFactory* message_loop_factory,
     media::FilterCollection* filter_collection,
-    media::AesDecryptor* decryptor,
+    media::Decryptor* decryptor,
     scoped_refptr<media::FFmpegVideoDecoder>* video_decoder);
 
 }  // webkit_media
 
 #endif  // WEBKIT_MEDIA_FILTER_HELPERS_H_