Add support for the audio-output-device switching IPC mechanism to the renderer lower layers (media…

media/audio/audio_output_device.cc

Index: media/audio/audio_output_device.cc
diff --git a/media/audio/audio_output_device.cc b/media/audio/audio_output_device.cc
index d55d10077ed47870fb34521fce57bc24ae4d71c8..3e43c06c9b5d4982808e1daf9fc043585d0668d6 100644
--- a/media/audio/audio_output_device.cc
+++ b/media/audio/audio_output_device.cc
@@ -4,6 +4,8 @@
 
 #include "media/audio/audio_output_device.h"
 
+#include <string>
+
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
@@ -45,7 +47,8 @@ AudioOutputDevice::AudioOutputDevice(
       state_(IDLE),
       play_on_start_(true),
       session_id_(-1),
-      stopping_hack_(false) {
+      stopping_hack_(false),
+      current_switch_request_id_(0) {
   CHECK(ipc_);
 
   // The correctness of the code depends on the relative values assigned in the
@@ -75,6 +78,14 @@ AudioOutputDevice::~AudioOutputDevice() {
   // The current design requires that the user calls Stop() before deleting
   // this class.
   DCHECK(audio_thread_.IsStopped());
+
+  // The following makes it possible for |current_switch_callback_| to release
+  // its bound parameters in the correct thread instead of implicitly releasing
+  // them in the thread where this destructor runs.
+  if (current_switch_callback_) {
+    current_switch_callback_->Run(SWITCH_OUTPUT_DEVICE_RESULT_ERROR_OBSOLETE);

[DaleCurtis, 2015/06/15 16:58:30]

you can use base::ResetAndReturn() to achieve this.

+    current_switch_callback_ = NULL;
+  }
 }
 
 void AudioOutputDevice::Start() {
@@ -117,6 +128,16 @@ bool AudioOutputDevice::SetVolume(double volume) {
   return true;
 }
 
+void AudioOutputDevice::SwitchOutputDevice(
+    const std::string& device_id,
+    const GURL& security_origin,
+    const SwitchOutputDeviceCB& callback) {
+  DVLOG(1) << __FUNCTION__ << "(" << device_id << ")";
+  task_runner()->PostTask(
+      FROM_HERE, base::Bind(&AudioOutputDevice::SwitchOutputDeviceOnIOThread,
+                            this, device_id, security_origin, callback));
+}
+
 void AudioOutputDevice::CreateStreamOnIOThread(const AudioParameters& params) {
   DCHECK(task_runner()->BelongsToCurrentThread());
   if (state_ == IDLE) {
@@ -179,6 +200,21 @@ void AudioOutputDevice::SetVolumeOnIOThread(double volume) {
     ipc_->SetVolume(volume);
 }
 
+void AudioOutputDevice::SwitchOutputDeviceOnIOThread(
+    const std::string& device_id,
+    const GURL& security_origin,
+    const SwitchOutputDeviceCB& callback) {
+  DCHECK(task_runner()->BelongsToCurrentThread());
+  DVLOG(1) << __FUNCTION__ << "(" << device_id << "," << security_origin << ")";
+  if (state_ >= CREATING_STREAM) {
+    SetCurrentSwitchRequest(callback);
+    ipc_->SwitchOutputDevice(device_id, security_origin,
+                             current_switch_request_id_);
+  } else {
+    callback.Run(SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_SUPPORTED);
+  }
+}
+
 void AudioOutputDevice::OnStateChanged(AudioOutputIPCDelegateState state) {
   DCHECK(task_runner()->BelongsToCurrentThread());
 
@@ -254,6 +290,32 @@ void AudioOutputDevice::OnStreamCreated(
     PlayOnIOThread();
 }
 
+void AudioOutputDevice::SetCurrentSwitchRequest(
+    const SwitchOutputDeviceCB& callback) {
+  DCHECK(task_runner()->BelongsToCurrentThread());
+  DVLOG(1) << __FUNCTION__;
+  // If there is a previous unresolved request, resolve it as obsolete
+  if (current_switch_callback_) {
+    current_switch_callback_->Run(SWITCH_OUTPUT_DEVICE_RESULT_ERROR_OBSOLETE);
+  }
+  current_switch_callback_.reset(new SwitchOutputDeviceCB(callback));
+  current_switch_request_id_++;
+}
+
+void AudioOutputDevice::OnOutputDeviceSwitched(
+    int request_id,
+    SwitchOutputDeviceResult result) {
+  DCHECK(task_runner()->BelongsToCurrentThread());
+  DCHECK(request_id <= current_switch_request_id_);
+  DVLOG(1) << __FUNCTION__
+           << "(" << request_id << ", " << result << ")";
+  if (request_id != current_switch_request_id_) {
+    return;
+  }
+  current_switch_callback_->Run(result);
+  current_switch_callback_ = NULL;
+}
+
 void AudioOutputDevice::OnIPCClosed() {
   DCHECK(task_runner()->BelongsToCurrentThread());
   state_ = IPC_CLOSED;