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

components/arc/bluetooth/arc_bluetooth_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/bluetooth/arc_bluetooth_bridge.h"
 
 #include <bluetooth/bluetooth.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <sys/socket.h>
@@ skipping 162 matching lines @@
   return 0 <= offset && offset < kMaxGattAttributeLength;
 }
 
 }  // namespace
 
 namespace arc {
 
 ArcBluetoothBridge::ArcBluetoothBridge(ArcBridgeService* bridge_service)
     : ArcService(bridge_service), binding_(this), weak_factory_(this) {
   if (BluetoothAdapterFactory::IsBluetoothAdapterAvailable()) {
-    VLOG(1) << "registering bluetooth adapter";
+    VLOG(1) << "Registering bluetooth adapter.";
     BluetoothAdapterFactory::GetAdapter(base::Bind(
         &ArcBluetoothBridge::OnAdapterInitialized, weak_factory_.GetWeakPtr()));
   } else {
-    VLOG(1) << "no bluetooth adapter available";
+    VLOG(1) << "No bluetooth adapter available.";
   }
-
   arc_bridge_service()->bluetooth()->AddObserver(this);
 }
 
 ArcBluetoothBridge::~ArcBluetoothBridge() {
   DCHECK(CalledOnValidThread());
 
   arc_bridge_service()->bluetooth()->RemoveObserver(this);
 
   if (bluetooth_adapter_)
     bluetooth_adapter_->RemoveObserver(this);
 }
 
 void ArcBluetoothBridge::OnAdapterInitialized(
     scoped_refptr<BluetoothAdapter> adapter) {
   DCHECK(CalledOnValidThread());
 
   // We can downcast here because we are always running on Chrome OS, and
   // so our adapter uses BlueZ.
   bluetooth_adapter_ =
       static_cast<bluez::BluetoothAdapterBlueZ*>(adapter.get());
-  bluetooth_adapter_->AddObserver(this);
+
+  // The ARC instance was ready before the Bluetooth adapter, hence we didn't
+  // register ourselves as an observer with it then. Since our adapter is
+  // ready, we should register it now.
+  if (!bluetooth_adapter_->HasObserver(this) &&
+      arc_bridge_service()->bluetooth()->instance()) {
+    bluetooth_adapter_->AddObserver(this);
+  }
 }
 
 void ArcBluetoothBridge::OnInstanceReady() {
   mojom::BluetoothInstance* bluetooth_instance =
       arc_bridge_service()->bluetooth()->instance();
   if (!bluetooth_instance) {
     LOG(ERROR) << "OnBluetoothInstanceReady called, "
                << "but no bluetooth instance found";
     return;
   }
+
   bluetooth_instance->Init(binding_.CreateInterfacePtrAndBind());
+
+  // The Bluetooth adapter was ready before the ARC instance, hence we didn't
+  // register ourselves as an observer with it then. Since our instance is
+  // ready, we should register it now.
+  if (bluetooth_adapter_ && !bluetooth_adapter_->HasObserver(this))
+    bluetooth_adapter_->AddObserver(this);
+}
+
+void ArcBluetoothBridge::OnInstanceClosed() {
+  if (bluetooth_adapter_)
+    bluetooth_adapter_->RemoveObserver(this);
 }
 
 void ArcBluetoothBridge::AdapterPoweredChanged(BluetoothAdapter* adapter,
                                                bool powered) {
   if (!HasBluetoothInstance())
     return;
 
   // TODO(smbarber): Invoke EnableAdapter or DisableAdapter via ARC bridge
   // service.
 }
@@ skipping 1408 matching lines @@
   LOG(WARNING) << "Bluetooth instance is too old (version " << version
                << ") need version " << version_need;
   return false;
 }
 
 bool ArcBluetoothBridge::CalledOnValidThread() {
   return thread_checker_.CalledOnValidThread();
 }
 
 }  // namespace arc