Fix erratic HTML5 audio playback

media/audio/audio_output_dispatcher.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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/audio/audio_output_dispatcher.h"
 
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "media/audio/audio_io.h"
 
 AudioOutputDispatcher::AudioOutputDispatcher(
@@ skipping 42 matching lines @@
 
   // Schedule task to allocate streams for other proxies if we need to.
   message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
       this, &AudioOutputDispatcher::OpenTask));
 
   return stream;
 }
 
 void AudioOutputDispatcher::StreamStopped(AudioOutputStream* stream) {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
+
   paused_proxies_++;
+
+  idle_streams_.push_front(stream);

[Sergey Ulanov, 2011/04/09 07:02:05]

Looks to me that we may leak streams that are in idle_streams_ when dispatcher
is destroyed. Normally  StreamClosed() ensures that streams are destroyed
necessary, but it would not happen with this change, because unused streams may
be in idle_streams_

+
+  // Don't recycle stream until two buffers worth of time has elapsed

[Sergey Ulanov, 2011/04/09 07:02:05]

nit: period at the end of the comment.

+  message_loop_->PostDelayedTask(FROM_HERE, NewRunnableMethod(
+      this, &AudioOutputDispatcher::StopStreamTask),
+      2 * params_.samples_per_packet * 1000 / params_.sample_rate);

[Sergey Ulanov, 2011/04/09 07:02:05]

nit: This line is not indented properly. I would move FROM_HERE to a separate
line.

[Sergey Ulanov, 2011/04/09 07:02:05]

nit: replace 1000 with Time::kMillisecondsPerSecond from base/time.h

[scherkus (not reviewing), 2011/04/11 22:32:33]

it looks like you can pre-calculate this since params_ is passed in via the ctor
and (shouldn't) change

+}
+
+void AudioOutputDispatcher::StopStreamTask() {
+  if (idle_streams_.empty())
+    return;
+  AudioOutputStream* stream = idle_streams_.back();
+  idle_streams_.pop_back();
   streams_.push_back(stream);
   close_timer_.Reset();
 }
 
 void AudioOutputDispatcher::StreamClosed() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
 
   DCHECK_GT(paused_proxies_, 0u);
   paused_proxies_--;
 
@@ skipping 31 matching lines @@
   close_timer_.Reset();
 }
 
 // This method is called by |close_timer_|.
 void AudioOutputDispatcher::ClosePendingStreams() {
   while (!streams_.empty()) {
     streams_.back()->Close();
     streams_.pop_back();
   }
 }