Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/audio_input_device_manager.cc

Index: content/browser/renderer_host/media/audio_input_device_manager.cc
diff --git a/content/browser/renderer_host/media/audio_input_device_manager.cc b/content/browser/renderer_host/media/audio_input_device_manager.cc
index 00e37f9a5c5f8cec6f6950a7ff1cb1add97d0a5b..364786e3e2a960ba767c9c3802ecafe11cc1c5b3 100644
--- a/content/browser/renderer_host/media/audio_input_device_manager.cc
+++ b/content/browser/renderer_host/media/audio_input_device_manager.cc
@@ -6,10 +6,12 @@
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/browser/browser_main_loop.h"
 #include "content/browser/renderer_host/media/audio_input_device_manager_event_handler.h"
 #include "content/public/browser/browser_thread.h"
 #include "media/audio/audio_manager_base.h"
 
+using content::BrowserMainLoop;
 using content::BrowserThread;
 
 namespace media_stream {
@@ -22,10 +24,10 @@ const char AudioInputDeviceManager::kInvalidDeviceId[] = "";
 const int kFirstSessionId = AudioInputDeviceManager::kFakeOpenSessionId + 1;
 
 AudioInputDeviceManager::AudioInputDeviceManager(
-    media::AudioManager* audio_manager)
+    scoped_refptr<base::MessageLoopProxy> message_loop)
     : listener_(NULL),
       next_capture_session_id_(kFirstSessionId),
-      audio_manager_(audio_manager) {
+      message_loop_(message_loop) {
 }
 
 AudioInputDeviceManager::~AudioInputDeviceManager() {
@@ -47,8 +49,38 @@ void AudioInputDeviceManager::EnumerateDevices() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(listener_);
 
+  message_loop_->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioInputDeviceManager::EnumerateOnDeviceThread, this));
+}
+
+int AudioInputDeviceManager::Open(const StreamDeviceInfo& device) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  // Generates a new id for this device.
+  int session_id = next_capture_session_id_++;
+  message_loop_->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioInputDeviceManager::OpenOnDeviceThread,
+                 this, session_id, device));
+
+  return session_id;
+}
+
+void AudioInputDeviceManager::Close(int session_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(listener_);
+  message_loop_->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioInputDeviceManager::CloseOnDeviceThread,
+                 this, session_id));
+}
+
+void AudioInputDeviceManager::EnumerateOnDeviceThread() {
+  DCHECK(IsOnDeviceThread());
+
+  // TODO(xians): Ensure AudioManager outlives MediaStreamManager.
   media::AudioDeviceNames device_names;
-  audio_manager_->GetAudioInputDeviceNames(&device_names);
+  BrowserMainLoop::GetAudioManager()->GetAudioInputDeviceNames(&device_names);
 
   StreamDeviceInfoArray* devices = new StreamDeviceInfoArray;
   for (media::AudioDeviceNames::iterator it = device_names.begin();
@@ -69,19 +101,14 @@ void AudioInputDeviceManager::EnumerateDevices() {
                  devices));
 }
 
-int AudioInputDeviceManager::Open(const StreamDeviceInfo& device) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  // Generates a new id for this device.
-  int session_id = next_capture_session_id_++;
+void AudioInputDeviceManager::OpenOnDeviceThread(
+    int session_id, const StreamDeviceInfo& device) {
+  DCHECK(IsOnDeviceThread());
   DCHECK(devices_.find(session_id) == devices_.end());
 
-  media::AudioDeviceName audio_input_device_name;
-  audio_input_device_name.device_name = device.name;
-  audio_input_device_name.unique_id = device.device_id;
-
   // Adds the session_id and device to the list.
-  devices_[session_id] = audio_input_device_name;
+  media::AudioDeviceName target_device(device.name, device.device_id);
+  devices_[session_id] = target_device;
 
   // Returns the |session_id| through the listener by posting a task on
   // IO thread since MediaStreamManager handles the callback asynchronously.
@@ -90,13 +117,10 @@ int AudioInputDeviceManager::Open(const StreamDeviceInfo& device) {
                           base::Bind(&AudioInputDeviceManager::OpenedOnIOThread,
                                      this,
                                      session_id));
-
-  return session_id;
 }
 
-void AudioInputDeviceManager::Close(int session_id) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK(listener_);
+void AudioInputDeviceManager::CloseOnDeviceThread(int session_id) {
+  DCHECK(IsOnDeviceThread());
 
   if (devices_.find(session_id) != devices_.end())
     devices_.erase(session_id);
@@ -181,4 +205,8 @@ void AudioInputDeviceManager::ClosedOnIOThread(int session_id) {
                       session_id);
 }
 
+bool AudioInputDeviceManager::IsOnDeviceThread() const {
+  return message_loop_->BelongsToCurrentThread();
+}
+
 }  // namespace media_stream