Always use arc::InstanceHolder<T>::GetInstanceForMethod

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/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm_shell.h"
 #include "base/logging.h"
 #include "chromeos/audio/audio_device.h"
 
 namespace arc {
 
+namespace {
+
+// Note: unlike most of our mojom definitions, AudioInstance::Init's minimum
+// version is not zero.
+constexpr uint32_t kMinInstanceVersionForInit = 1;
+
+}  // namespace
+
 ArcAudioBridge::ArcAudioBridge(ArcBridgeService* bridge_service)
     : ArcService(bridge_service), binding_(this) {
   arc_bridge_service()->audio()->AddObserver(this);
   if (chromeos::CrasAudioHandler::IsInitialized()) {
     cras_audio_handler_ = chromeos::CrasAudioHandler::Get();
     cras_audio_handler_->AddAudioObserver(this);
   }
 }
 
 ArcAudioBridge::~ArcAudioBridge() {
   if (cras_audio_handler_ && chromeos::CrasAudioHandler::IsInitialized()) {
     cras_audio_handler_->RemoveAudioObserver(this);
   }
   arc_bridge_service()->audio()->RemoveObserver(this);
 }
 
 void ArcAudioBridge::OnInstanceReady() {
   mojom::AudioInstance* audio_instance =
-      arc_bridge_service()->audio()->instance();
-  if (!audio_instance) {
-    LOG(ERROR) << "OnAudioInstanceReady called, "
-               << "but no audio instance found";
-    return;
-  }
-  if (arc_bridge_service()->audio()->version() < 1) {
-    LOG(WARNING) << "Audio instance is too old and does not support Init()";
-    return;
-  }
+      arc_bridge_service()->audio()->GetInstanceForMethod(
+          "Init", kMinInstanceVersionForInit);
+  DCHECK(audio_instance);  // the instance on ARC side is too old.
   audio_instance->Init(binding_.CreateInterfacePtrAndBind());
 }
 
 void ArcAudioBridge::ShowVolumeControls() {
   VLOG(2) << "ArcAudioBridge::ShowVolumeControls";
   ash::WmShell::Get()->system_tray_notifier()->NotifyAudioOutputVolumeChanged(
       0, 0);
 }
 
 void ArcAudioBridge::OnAudioNodesChanged() {
@@ skipping 23 matching lines @@
     switch_state |=
         (1 << static_cast<uint32_t>(mojom::AudioSwitch::SW_HEADPHONE_INSERT));
   }
   if (microphone_inserted) {
     switch_state |=
         (1 << static_cast<uint32_t>(mojom::AudioSwitch::SW_MICROPHONE_INSERT));
   }
 
   VLOG(1) << "Send switch state " << switch_state;
   mojom::AudioInstance* audio_instance =
-      arc_bridge_service()->audio()->instance();
+      arc_bridge_service()->audio()->GetInstanceForMethod("NotifySwitchState");
   if (audio_instance)
     audio_instance->NotifySwitchState(switch_state);
 }
 
 }  // namespace arc