Support encrypted audio stream in demuxer.

media/webm/webm_stream_parser.cc

Index: media/webm/webm_stream_parser.cc
diff --git a/media/webm/webm_stream_parser.cc b/media/webm/webm_stream_parser.cc
index b0a18e3659860bd0a653bacc1981b274960b9464..514f9401fa339f4281b48569e7b9c803aa0d8adc 100644
--- a/media/webm/webm_stream_parser.cc
+++ b/media/webm/webm_stream_parser.cc
@@ -19,6 +19,16 @@
 
 namespace media {
 
+// Fire needkey event through the |need_key_cb|.
+static void FireNeedKey(const StreamParser::NeedKeyCB& need_key_cb,
+                        const std::string& key_id) {
+  int key_id_size = key_id.size();
+  DCHECK_GT(key_id_size, 0);
+  scoped_array<uint8> key_id_array(new uint8[key_id_size]);
+  memcpy(key_id_array.get(), key_id.data(), key_id_size);
+  need_key_cb.Run(key_id_array.Pass(), key_id_size);
+}
+
 // Helper class that uses FFmpeg to create AudioDecoderConfig &
 // VideoDecoderConfig objects.
 //
@@ -351,6 +361,25 @@ int WebMStreamParser::ParseInfoAndTracks(const uint8* data, int size) {
     return -1;
   }
 
+  bool is_audio_encrypted = !tracks_parser.audio_encryption_key_id().empty();
+  AudioDecoderConfig audio_config;
+  if (is_audio_encrypted) {
+    const AudioDecoderConfig& original_audio_config =
+        config_helper.audio_config();
+
+    audio_config.Initialize(original_audio_config.codec(),
+                            original_audio_config.bits_per_channel(),
+                            original_audio_config.channel_layout(),
+                            original_audio_config.samples_per_second(),
+                            original_audio_config.extra_data(),
+                            original_audio_config.extra_data_size(),
+                            is_audio_encrypted, false);
+
+    FireNeedKey(need_key_cb_, tracks_parser.audio_encryption_key_id());

[acolwell GONE FROM CHROMIUM, 2012/10/11 01:11:24]

nit: Why are you using a static function here instead of a member function? 

[xhwang, 2012/10/11 16:36:10]

Done.

+  } else {
+    audio_config.CopyFrom(config_helper.audio_config());
+  }
+
   // TODO(xhwang): Support decryption of audio (see http://crbug.com/123421).
   bool is_video_encrypted = !tracks_parser.video_encryption_key_id().empty();
 
@@ -368,18 +397,12 @@ int WebMStreamParser::ParseInfoAndTracks(const uint8* data, int size) {
                             original_video_config.extra_data_size(),
                             is_video_encrypted, false);
 
-    // Fire needkey event.
-    std::string key_id = tracks_parser.video_encryption_key_id();
-    int key_id_size = key_id.size();
-    DCHECK_GT(key_id_size, 0);
-    scoped_array<uint8> key_id_array(new uint8[key_id_size]);
-    memcpy(key_id_array.get(), key_id.data(), key_id_size);
-    need_key_cb_.Run(key_id_array.Pass(), key_id_size);
+    FireNeedKey(need_key_cb_, tracks_parser.video_encryption_key_id());
   } else {
     video_config.CopyFrom(config_helper.video_config());
   }
 
-  if (!config_cb_.Run(config_helper.audio_config(), video_config)) {
+  if (!config_cb_.Run(audio_config, video_config)) {
     DVLOG(1) << "New config data isn't allowed.";
     return -1;
   }
@@ -388,6 +411,7 @@ int WebMStreamParser::ParseInfoAndTracks(const uint8* data, int size) {
       info_parser.timecode_scale(),
       tracks_parser.audio_track_num(),
       tracks_parser.video_track_num(),
+      tracks_parser.audio_encryption_key_id(),
       tracks_parser.video_encryption_key_id()));
 
   ChangeState(kParsingClusters);