MSE: Protect better against reaching HAVE_METADATA too early

media/filters/chunk_demuxer.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 "media/filters/chunk_demuxer.h"
 
 #include <algorithm>
 #include <limits>
 #include <list>
 #include <utility>
@@ skipping 347 matching lines @@
     const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
     const scoped_refptr<MediaLog>& media_log,
     bool splice_frames_enabled)
     : state_(WAITING_FOR_INIT),
       cancel_next_seek_(false),
       host_(NULL),
       open_cb_(open_cb),
       encrypted_media_init_data_cb_(encrypted_media_init_data_cb),
       enable_text_(false),
       media_log_(media_log),
+      pending_source_init_done_count_(0),
       duration_(kNoTimestamp()),
       user_specified_duration_(-1),
       liveness_(DemuxerStream::LIVENESS_UNKNOWN),
       splice_frames_enabled_(splice_frames_enabled),
       detected_audio_track_count_(0),
       detected_video_track_count_(0),
       detected_text_track_count_(0) {
   DCHECK(!open_cb_.is_null());
   DCHECK(!encrypted_media_init_data_cb_.is_null());
 }
@@ skipping 160 matching lines @@
       base::Bind(&ChunkDemuxer::CreateDemuxerStream, base::Unretained(this)),
       media_log_));
 
   MediaSourceState::NewTextTrackCB new_text_track_cb;
 
   if (enable_text_) {
     new_text_track_cb = base::Bind(&ChunkDemuxer::OnNewTextTrack,
                                    base::Unretained(this));
   }
 
+  pending_source_init_done_count_++;
+
   source_state->Init(
       base::Bind(&ChunkDemuxer::OnSourceInitDone, base::Unretained(this)),
       has_audio, has_video, encrypted_media_init_data_cb_, new_text_track_cb);
 
   source_state_map_[id] = source_state.release();
   return kOk;
 }
 
 void ChunkDemuxer::SetTracksWatcher(
     const std::string& id,
@@ skipping 405 matching lines @@
       audio_->SetLiveness(params.liveness);
     if (video_)
       video_->SetLiveness(params.liveness);
   }
 
   detected_audio_track_count_ += params.detected_audio_track_count;
   detected_video_track_count_ += params.detected_video_track_count;
   detected_text_track_count_ += params.detected_text_track_count;
 
   // Wait until all streams have initialized.
-  // TODO(wolenetz): Make this gate less fragile. See https://crbug.com/597447.
-  if ((!source_id_audio_.empty() && !audio_) ||
-      (!source_id_video_.empty() && !video_)) {
+  pending_source_init_done_count_--;
+
+  if (pending_source_init_done_count_ > 0)
     return;
-  }
+
+  DCHECK_EQ(0, pending_source_init_done_count_);
+  DCHECK((source_id_audio_.empty() == !audio_) &&
+         (source_id_video_.empty() == !video_));
 
   // Record detected track counts by type corresponding to an MSE playback.
   // Counts are split into 50 buckets, capped into [0,100] range.
   UMA_HISTOGRAM_COUNTS_100("Media.MSE.DetectedTrackCount.Audio",
                            detected_audio_track_count_);
   UMA_HISTOGRAM_COUNTS_100("Media.MSE.DetectedTrackCount.Video",
                            detected_video_track_count_);
   UMA_HISTOGRAM_COUNTS_100("Media.MSE.DetectedTrackCount.Text",
                            detected_text_track_count_);
 
@@ skipping 145 matching lines @@
 }
 
 void ChunkDemuxer::ShutdownAllStreams() {
   for (MediaSourceStateMap::iterator itr = source_state_map_.begin();
        itr != source_state_map_.end(); ++itr) {
     itr->second->Shutdown();
   }
 }
 
 }  // namespace media