media config: expand is_encrypted to a struct.

media/formats/webm/webm_tracks_parser.cc

Index: media/formats/webm/webm_tracks_parser.cc
diff --git a/media/formats/webm/webm_tracks_parser.cc b/media/formats/webm/webm_tracks_parser.cc
index 464a77ff1e66eab49ff8a43358508f76e509bad9..f43ea306085470ff76b5ec2c316cc1533f8b6346 100644
--- a/media/formats/webm/webm_tracks_parser.cc
+++ b/media/formats/webm/webm_tracks_parser.cc
@@ -192,6 +192,10 @@ bool WebMTracksParser::OnListEnd(int id) {
           content_encodings()[0]->encryption_key_id();
     }
 
+    EncryptionScheme encryption_scheme(
+        encryption_key_id.empty() ? EncryptionScheme::kCipherModeUnencrypted
+                                  : EncryptionScheme::kCipherModeAesCtr);
+
     if (track_type_ == kWebMTrackTypeAudio) {
       if (audio_track_num_ == -1) {
         audio_track_num_ = track_num_;
@@ -207,7 +211,7 @@ bool WebMTracksParser::OnListEnd(int id) {
         DCHECK(!audio_decoder_config_.IsValidConfig());
         if (!audio_client_.InitializeConfig(
                 codec_id_, codec_private_, seek_preroll_, codec_delay_,
-                !audio_encryption_key_id_.empty(), &audio_decoder_config_)) {
+                encryption_scheme, &audio_decoder_config_)) {
           return false;
         }
       } else {
@@ -227,9 +231,9 @@ bool WebMTracksParser::OnListEnd(int id) {
         video_default_duration_ = default_duration_;
 
         DCHECK(!video_decoder_config_.IsValidConfig());
-        if (!video_client_.InitializeConfig(
-                codec_id_, codec_private_, !video_encryption_key_id_.empty(),
-                &video_decoder_config_)) {
+        if (!video_client_.InitializeConfig(codec_id_, codec_private_,
+                                            encryption_scheme,
+                                            &video_decoder_config_)) {
           return false;
         }
       } else {