Fix double StopStream() calls during wedge fix.

Whoops.  The wedge fix ignored start / stop status when stopping
streams which leads to heap corruption when the underlying dispatcher
tries to stop a stream it can't find in the audio stream map.

BUG=326656
TEST=new unittest
NOTRY=true

Review URL: https://codereview.chromium.org/109113002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239342 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 2 deletions

diff --git a/media/audio/audio_output_resampler.cc b/media/audio/audio_output_resampler.cc
index 3179ddb..c53f3e0 100644
--- a/media/audio/audio_output_resampler.cc
+++ b/media/audio/audio_output_resampler.cc
@@ -43,6 +43,8 @@ class OnMoreDataConverter
   // Clears |source_callback_| and flushes the resampler.
   void Stop();
 
+  bool started() { return source_callback_ != NULL; }
+
  private:
   // AudioConverter::InputCallback implementation.
   virtual double ProvideInput(AudioBus* audio_bus,
@@ -298,7 +300,8 @@ void AudioOutputResampler::CloseStreamsForWedgeFix() {
   // have been closed the AudioManager will call RestartStreamsForWedgeFix().
   for (CallbackMap::iterator it = callbacks_.begin(); it != callbacks_.end();
        ++it) {
-    dispatcher_->StopStream(it->first);
+    if (it->second->started())
+      dispatcher_->StopStream(it->first);
     dispatcher_->CloseStream(it->first);
   }
 
@@ -308,10 +311,16 @@ void AudioOutputResampler::CloseStreamsForWedgeFix() {
 
 void AudioOutputResampler::RestartStreamsForWedgeFix() {
   DCHECK(message_loop_->BelongsToCurrentThread());
+  // By opening all streams first and then starting them one by one we ensure
+  // the dispatcher only opens streams for those which will actually be used.
   for (CallbackMap::iterator it = callbacks_.begin(); it != callbacks_.end();
        ++it) {
     dispatcher_->OpenStream();
-    dispatcher_->StartStream(it->second, it->first);
+  }
+  for (CallbackMap::iterator it = callbacks_.begin(); it != callbacks_.end();
+       ++it) {
+    if (it->second->started())
+      dispatcher_->StartStream(it->second, it->first);
   }
 }