Fix hangs & crashes in teardown-during-Seek.

content/renderer/media/audio_renderer_impl.cc

Index: content/renderer/media/audio_renderer_impl.cc
diff --git a/content/renderer/media/audio_renderer_impl.cc b/content/renderer/media/audio_renderer_impl.cc
index ac6aca0f271b6364f12c111a24386fe27a3274a8..2aaa12f99593476422ae2bd737699c81d4800cdf 100644
--- a/content/renderer/media/audio_renderer_impl.cc
+++ b/content/renderer/media/audio_renderer_impl.cc
@@ -98,18 +98,28 @@ bool AudioRendererImpl::OnInitialize(int bits_per_channel,
 }
 
 void AudioRendererImpl::OnStop() {
-  base::AutoLock auto_lock(lock_);
-  if (stopped_)
-    return;
-  stopped_ = true;
-
-  ChildProcess::current()->io_message_loop()->PostTask(
-      FROM_HERE,
-      NewRunnableMethod(this, &AudioRendererImpl::DestroyTask));
+  // Since joining with the audio thread can acquire lock_, we make sure to
+  // Join() with it not under lock.
+  base::DelegateSimpleThread* audio_thread = NULL;
+  base::SyncSocket* socket = NULL;
+  {
+    base::AutoLock auto_lock(lock_);
+    if (stopped_)
+      return;
+    stopped_ = true;
+    DCHECK_EQ(!audio_thread_.get(), !socket_.get());
+    if (audio_thread_.get()) {
+      audio_thread = audio_thread_.get();
+      socket = socket_.get();
+    }
+    ChildProcess::current()->io_message_loop()->PostTask(
+        FROM_HERE,
+        NewRunnableMethod(this, &AudioRendererImpl::DestroyTask));
+  }
 
-  if (audio_thread_.get()) {
-    socket_->Close();
-    audio_thread_->Join();
+  if (audio_thread) {
+    CHECK(socket->Close());

[acolwell GONE FROM CHROMIUM, 2011/10/07 15:50:47]

Does this need to happen outside of the lock?

[Ami GONE FROM CHROMIUM, 2011/10/07 16:44:47]

Done.

+    audio_thread->Join();
   }
 }
 
@@ -455,6 +465,7 @@ void AudioRendererImpl::WillDestroyCurrentMessageLoop() {
 // Our audio thread runs here. We receive requests for more data and send it
 // on this thread.
 void AudioRendererImpl::Run() {
+  DCHECK_EQ(kLowLatency, latency_type_);
   audio_thread_->SetThreadPriority(base::kThreadPriority_RealtimeAudio);
 
   int bytes;