Adding ArcBridge Interface for Volume Update Requests

components/arc/audio/arc_audio_bridge.cc

 // Copyright 2016 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 "components/arc/audio/arc_audio_bridge.h"
 
 #include "ash/system/audio/tray_audio.h"
 #include "base/logging.h"
 #include "chromeos/audio/audio_device.h"
 #include "components/arc/arc_bridge_service.h"
@@ skipping 21 matching lines @@
       ARC_GET_INSTANCE_FOR_METHOD(arc_bridge_service()->audio(), Init);
   DCHECK(audio_instance);  // the instance on ARC side is too old.
   audio_instance->Init(binding_.CreateInterfacePtrAndBind());
 }
 
 void ArcAudioBridge::ShowVolumeControls() {
   DVLOG(2) << "ArcAudioBridge::ShowVolumeControls";
   ash::TrayAudio::ShowPopUpVolumeView();
 }
 
+void ArcAudioBridge::OnSystemVolumeUpdateRequest(int32_t percent) {
+  if (percent < 0 || percent > 100)
+    return;
+  cras_audio_handler_->SetOutputVolumePercent(percent);
+  bool is_muted =
+      percent <= cras_audio_handler_->GetOutputDefaultVolumeMuteThreshold();

[dcheng, 2017/06/06 18:45:38]

FWIW, it seems like this is already down in CrasAudioHandler:
https://cs.chromium.org/chromium/src/chromeos/audio/cras_audio_handler.cc?rcl...

[yueli, 2017/06/06 20:01:40]

IIUC SetOutputMute will change the device mute settings, which is not equivalent
to set volume to 0.

+  if (cras_audio_handler_->IsOutputMuted() != is_muted)
+    cras_audio_handler_->SetOutputMute(is_muted);
+}
+
 void ArcAudioBridge::OnAudioNodesChanged() {
   uint64_t output_id = cras_audio_handler_->GetPrimaryActiveOutputNode();
   const chromeos::AudioDevice* output_device =
       cras_audio_handler_->GetDeviceFromId(output_id);
   bool headphone_inserted =
       (output_device &&
        output_device->type == chromeos::AudioDeviceType::AUDIO_TYPE_HEADPHONE);
 
   uint64_t input_id = cras_audio_handler_->GetPrimaryActiveInputNode();
   const chromeos::AudioDevice* input_device =
@@ skipping 40 matching lines @@
 
 void ArcAudioBridge::SendVolumeState() {
   DVLOG(1) << "Send volume " << volume_ << " muted " << muted_;
   mojom::AudioInstance* audio_instance = ARC_GET_INSTANCE_FOR_METHOD(
       arc_bridge_service()->audio(), NotifyVolumeState);
   if (audio_instance)
     audio_instance->NotifyVolumeState(volume_, muted_);
 }
 
 }  // namespace arc