Add support for config changes during playback to FFmpegVideoDecoder.

media/filters/source_buffer_stream.cc

Index: media/filters/source_buffer_stream.cc
diff --git a/media/filters/source_buffer_stream.cc b/media/filters/source_buffer_stream.cc
index c76842391532f3b235dc3c98322035dd14ed5e05..959d3b83697ef8d311f0e7bbd9911f18dbd44692 100644
--- a/media/filters/source_buffer_stream.cc
+++ b/media/filters/source_buffer_stream.cc
@@ -282,6 +282,7 @@ SourceBufferStream::SourceBufferStream(const AudioDecoderConfig& audio_config)
       last_buffer_timestamp_(kNoTimestamp()),
       max_interbuffer_distance_(kNoTimestamp()),
       memory_limit_(kDefaultAudioMemoryLimit) {
+  DCHECK(audio_config.IsValidConfig());
   audio_configs_[0] = new AudioDecoderConfig();

[Ami GONE FROM CHROMIUM, 2012/08/17 15:16:59]

FWIW, you could
audio_configs_.push_back(new AudioDecoderConfig());
audio_configs_.back()->CopyFrom(audio_config);
and drop the size ctor at l.273.
(and ditto for the VDC ctor below)

[acolwell GONE FROM CHROMIUM, 2012/08/20 23:10:12]

Done.

   audio_configs_[0]->CopyFrom(audio_config);
 }
@@ -301,6 +302,7 @@ SourceBufferStream::SourceBufferStream(const VideoDecoderConfig& video_config)
       last_buffer_timestamp_(kNoTimestamp()),
       max_interbuffer_distance_(kNoTimestamp()),
       memory_limit_(kDefaultVideoMemoryLimit) {
+  DCHECK(video_config.IsValidConfig());
   video_configs_[0] = new VideoDecoderConfig();
   video_configs_[0]->CopyFrom(video_config);
 }
@@ -736,6 +738,7 @@ void SourceBufferStream::Seek(base::TimeDelta timestamp) {
   DCHECK(timestamp >= stream_start_time_);
   SetSelectedRange(NULL);
   track_buffer_.clear();
+  config_change_pending_ = false;
 
   if (ShouldSeekToStartOfBuffered(timestamp)) {
     SetSelectedRange(ranges_.front());
@@ -768,8 +771,10 @@ bool SourceBufferStream::IsSeekPending() const {
 SourceBufferStream::Status SourceBufferStream::GetNextBuffer(
     scoped_refptr<StreamParserBuffer>* out_buffer) {
   if (!track_buffer_.empty()) {
-    if (track_buffer_.front()->GetConfigId() != current_config_index_)
+    if (track_buffer_.front()->GetConfigId() != current_config_index_) {
+      config_change_pending_ = true;
       return kConfigChange;
+    }
 
     *out_buffer = track_buffer_.front();
     track_buffer_.pop_front();
@@ -779,8 +784,10 @@ SourceBufferStream::Status SourceBufferStream::GetNextBuffer(
   if (!selected_range_ || !selected_range_->HasNextBuffer())
     return kNeedBuffer;
 
-  if (selected_range_->GetNextConfigId() != current_config_index_)
+  if (selected_range_->GetNextConfigId() != current_config_index_) {
+    config_change_pending_ = true;
     return kConfigChange;
+  }
 
   CHECK(selected_range_->GetNextBuffer(out_buffer));
   return kSuccess;
@@ -852,12 +859,14 @@ bool SourceBufferStream::IsEndSelected() const {
 }
 
 const AudioDecoderConfig& SourceBufferStream::GetCurrentAudioDecoderConfig() {
-  CompleteConfigChange();
+  if (config_change_pending_)
+    CompleteConfigChange();
   return *audio_configs_[current_config_index_];
 }
 
 const VideoDecoderConfig& SourceBufferStream::GetCurrentVideoDecoderConfig() {
-  CompleteConfigChange();
+  if (config_change_pending_)
+    CompleteConfigChange();
   return *video_configs_[current_config_index_];
 }
 
@@ -935,6 +944,7 @@ bool SourceBufferStream::UpdateVideoConfig(const VideoDecoderConfig& config) {
 void SourceBufferStream::CompleteConfigChange() {
   if (!track_buffer_.empty()) {
     current_config_index_ = track_buffer_.front()->GetConfigId();
+    config_change_pending_ = false;
     return;
   }
 
@@ -942,6 +952,7 @@ void SourceBufferStream::CompleteConfigChange() {
     return;
 
   current_config_index_ = selected_range_->GetNextConfigId();
+  config_change_pending_ = false;
 }
 
 SourceBufferRange::SourceBufferRange(