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..389a208ec23febdd23e4e323927cc419dcab362f 100644
--- a/components/arc/bluetooth/arc_bluetooth_bridge.cc
+++ b/components/arc/bluetooth/arc_bluetooth_bridge.cc
@@ -186,7 +186,6 @@ ArcBluetoothBridge::ArcBluetoothBridge(ArcBridgeService* bridge_service)
   } else {
     VLOG(1) << "no bluetooth adapter available";
   }
-
   arc_bridge_service()->bluetooth()->AddObserver(this);
 }
 
@@ -207,7 +206,14 @@ void ArcBluetoothBridge::OnAdapterInitialized(
   // so our adapter uses BlueZ.
   bluetooth_adapter_ =
       static_cast<bluez::BluetoothAdapterBlueZ*>(adapter.get());
-  bluetooth_adapter_->AddObserver(this);
+
+  // Arc instance is ready before Bluetooth adapter.
+  // We should register ourself to bluetooth observer here.

[Luis Héctor Chávez, 2016/08/08 21:12:03]

nit: s/ourself/ourselves/. Same below.

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

Done.

+  if (!bluetooth_observer_flag_ &&
+      arc_bridge_service()->bluetooth()->instance()) {
+    bluetooth_observer_flag_ = true;
+    bluetooth_adapter_->AddObserver(this);
+  }
 }
 
 void ArcBluetoothBridge::OnInstanceReady() {
@@ -218,7 +224,19 @@ void ArcBluetoothBridge::OnInstanceReady() {
                << "but no bluetooth instance found";
     return;
   }
-  bluetooth_instance->Init(binding_.CreateInterfacePtrAndBind());

[rkc, 2016/08/08 21:16:15]

Where are we doing this now?

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

My error. Fixed

+
+  // Bluetooth adapter is ready before Arc instance.
+  // We should register ourself to bluetooth observer here.
+  if (!bluetooth_observer_flag_ && bluetooth_adapter_) {
+    bluetooth_observer_flag_ = true;
+    bluetooth_adapter_->AddObserver(this);
+  }
+}
+
+void ArcBluetoothBridge::OnInstanceClosed() {
+  if (bluetooth_observer_flag_ && bluetooth_adapter_)

[Luis Héctor Chávez, 2016/08/08 21:12:03]

If you remove the flag like rkc@ suggested, maybe do bluetooth_adapter_.reset()
here.

[rkc, 2016/08/08 21:16:15]

+1

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

I changed to code to hold make bluetooth_adapter_ a valid pointer all the time.
Or else we need to add null check for bluetooth_adapter_ to every function.

+    bluetooth_adapter_->RemoveObserver(this);
+  bluetooth_observer_flag_ = false;
 }
 
 void ArcBluetoothBridge::AdapterPoweredChanged(BluetoothAdapter* adapter,