arc: bluetooth: Add/Remove BT observer only when ARC is ready

components/arc/bluetooth/arc_bluetooth_bridge.cc

Index: components/arc/bluetooth/arc_bluetooth_bridge.cc
diff --git a/components/arc/bluetooth/arc_bluetooth_bridge.cc b/components/arc/bluetooth/arc_bluetooth_bridge.cc
index dbc6747b662299696c5c1ebb56d1a9f069e3b04c..865217d7b0454952532c7b218728b470451172f4 100644
--- a/components/arc/bluetooth/arc_bluetooth_bridge.cc
+++ b/components/arc/bluetooth/arc_bluetooth_bridge.cc
@@ -179,14 +179,6 @@ namespace arc {
 
 ArcBluetoothBridge::ArcBluetoothBridge(ArcBridgeService* bridge_service)
     : ArcService(bridge_service), binding_(this), weak_factory_(this) {
-  if (BluetoothAdapterFactory::IsBluetoothAdapterAvailable()) {
-    VLOG(1) << "registering bluetooth adapter";
-    BluetoothAdapterFactory::GetAdapter(base::Bind(
-        &ArcBluetoothBridge::OnAdapterInitialized, weak_factory_.GetWeakPtr()));
-  } else {
-    VLOG(1) << "no bluetooth adapter available";
-  }
-
   arc_bridge_service()->bluetooth()->AddObserver(this);
 }
 
@@ -208,6 +200,7 @@ void ArcBluetoothBridge::OnAdapterInitialized(
   bluetooth_adapter_ =
       static_cast<bluez::BluetoothAdapterBlueZ*>(adapter.get());
   bluetooth_adapter_->AddObserver(this);
+  bluetooth_observer_flag_ = true;
 }
 
 void ArcBluetoothBridge::OnInstanceReady() {
@@ -219,6 +212,19 @@ void ArcBluetoothBridge::OnInstanceReady() {
     return;
   }
   bluetooth_instance->Init(binding_.CreateInterfacePtrAndBind());
+  if (BluetoothAdapterFactory::IsBluetoothAdapterAvailable()) {
+    VLOG(1) << "registering bluetooth adapter";

[rkc, 2016/08/08 21:08:12]

VLOG(1) << "Registering Bluetooth adapter.";

[puthik_chromium, 2016/08/08 21:40:25]

Done.

+    BluetoothAdapterFactory::GetAdapter(base::Bind(
+        &ArcBluetoothBridge::OnAdapterInitialized, weak_factory_.GetWeakPtr()));
+  } else {
+    VLOG(1) << "no bluetooth adapter available";

[rkc, 2016/08/08 21:08:12]

VLOG(1) << "No Bluetooth adapter available.";

[puthik_chromium, 2016/08/08 21:40:25]

Done.

+  }
+}
+
+void ArcBluetoothBridge::OnInstanceClosed() {
+  if (bluetooth_observer_flag_ && bluetooth_adapter_)
+    bluetooth_adapter_->RemoveObserver(this);

[rkc, 2016/08/08 21:08:12]

You don't need the bluetooth_observer_flag_ flag. If there is no observer
registered, RemoveObserver will do nothing.

[puthik_chromium, 2016/08/08 21:40:25]

The flag is used to see that we should register observer when bluetooth_adapter_
is ready or when arc_instance is ready. 

+  bluetooth_observer_flag_ = false;
 }
 
 void ArcBluetoothBridge::AdapterPoweredChanged(BluetoothAdapter* adapter,