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

2 files changed, 24 insertions, 5 deletions

diff --git a/media/audio/audio_output_proxy_unittest.cc b/media/audio/audio_output_proxy_unittest.cc
index 1c4029b..de690d9 100644
--- a/media/audio/audio_output_proxy_unittest.cc
+++ b/media/audio/audio_output_proxy_unittest.cc
@@ -771,6 +771,7 @@ TEST_F(AudioOutputResamplerTest, WedgeFix) {
   EXPECT_CALL(stream1, SetVolume(_));
   EXPECT_CALL(stream2, Open())
       .WillOnce(Return(true));
+  EXPECT_CALL(stream2, SetVolume(_));
   EXPECT_CALL(stream2, Close());
 
   // Open and start the first proxy and stream.
@@ -783,12 +784,20 @@ TEST_F(AudioOutputResamplerTest, WedgeFix) {
   AudioOutputProxy* proxy2 = new AudioOutputProxy(resampler_.get());
   EXPECT_TRUE(proxy2->Open());
 
+  // Open, start and then stop the third proxy.
+  AudioOutputProxy* proxy3 = new AudioOutputProxy(resampler_.get());
+  EXPECT_TRUE(proxy3->Open());
+  proxy3->Start(&callback_);
+  OnStart();
+  proxy3->Stop();
+
   // Wait for stream to timeout and shutdown.
   WaitForCloseTimer(kTestCloseDelayMs);
 
   resampler_->CloseStreamsForWedgeFix();
 
-  // Stream3 should take Stream1's place after RestartStreamsForWedgeFix().
+  // Stream3 should take Stream1's place after RestartStreamsForWedgeFix().  No
+  // additional streams should be opened for proxy2 and proxy3.
   EXPECT_CALL(stream3, Open())
       .WillOnce(Return(true));
   EXPECT_CALL(stream3, Close());
@@ -798,6 +807,7 @@ TEST_F(AudioOutputResamplerTest, WedgeFix) {
   OnStart();
 
   // Perform the required Stop()/Close() shutdown dance for each proxy.
+  proxy3->Close();
   proxy2->Close();
   proxy1->Stop();
   proxy1->Close();
@@ -806,8 +816,8 @@ TEST_F(AudioOutputResamplerTest, WedgeFix) {
   WaitForCloseTimer(kTestCloseDelayMs);
   EXPECT_TRUE(stream1.stop_called());
   EXPECT_TRUE(stream1.start_called());
-  EXPECT_FALSE(stream2.stop_called());
-  EXPECT_FALSE(stream2.start_called());
+  EXPECT_TRUE(stream2.stop_called());
+  EXPECT_TRUE(stream2.start_called());
   EXPECT_TRUE(stream3.stop_called());
   EXPECT_TRUE(stream3.start_called());
 }
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);
   }
 }