arc: bluetooth: Observe connections in a direct manner

It's a bit redundant to have a helper class to simply observe
the app and intent helper connections.

BUG=b:111367421
TEST=Bluetooth works

Change-Id: Ice714e43331c7590f8c08fd8ddaa59fbc31ec3e0
Reviewed-on: https://chromium-review.googlesource.com/c/1285087Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Commit-Queue: Qiyu Hu <qiyuh@google.com>
Cr-Commit-Position: refs/heads/master@{#600420}

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.cc

@@ -432,59 +432,11 @@ ArcBluetoothBridge* ArcBluetoothBridge::GetForBrowserContext(
   return ArcBluetoothBridgeFactory::GetForBrowserContext(context);
 }
 
-template <typename InstanceType, typename HostType>
-class ArcBluetoothBridge::ConnectionObserverImpl
-    : public ConnectionObserver<InstanceType> {
- public:
-  ConnectionObserverImpl(ArcBluetoothBridge* owner,
-                         ArcBridgeService* arc_bridge_service)
-      : owner_(owner), arc_bridge_service_(arc_bridge_service) {
-    GetHolder()->AddObserver(this);
-  }
-
-  ~ConnectionObserverImpl() override { GetHolder()->RemoveObserver(this); }
-
- protected:
-  ConnectionHolder<InstanceType, HostType>* GetHolder();
-
-  ArcBridgeService* arc_bridge_service() { return arc_bridge_service_; }
-
- private:
-  // ConnectionObserver<T>:
-  void OnConnectionReady() override { owner_->MaybeSendInitialPowerChange(); }
-
-  // Unowned pointer
-  ArcBluetoothBridge* const owner_;
-  ArcBridgeService* const arc_bridge_service_;
-
-  DISALLOW_COPY_AND_ASSIGN(ConnectionObserverImpl);
-};
-
-template <>
-ConnectionHolder<mojom::AppInstance, mojom::AppHost>*
-ArcBluetoothBridge::ConnectionObserverImpl<mojom::AppInstance,
-                                           mojom::AppHost>::GetHolder() {
-  return arc_bridge_service()->app();
-}
-
-template <>
-ConnectionHolder<mojom::IntentHelperInstance, mojom::IntentHelperHost>*
-ArcBluetoothBridge::ConnectionObserverImpl<
-    mojom::IntentHelperInstance,
-    mojom::IntentHelperHost>::GetHolder() {
-  return arc_bridge_service()->intent_helper();
-}
-
 ArcBluetoothBridge::ArcBluetoothBridge(content::BrowserContext* context,
                                        ArcBridgeService* bridge_service)
     : arc_bridge_service_(bridge_service), weak_factory_(this) {
-  app_observer_ = std::make_unique<
-      ConnectionObserverImpl<mojom::AppInstance, mojom::AppHost>>(
-      this, arc_bridge_service_);
-  intent_helper_observer_ =
-      std::make_unique<ConnectionObserverImpl<mojom::IntentHelperInstance,
-                                              mojom::IntentHelperHost>>(
-          this, arc_bridge_service_);
+  arc_bridge_service_->app()->AddObserver(this);
+  arc_bridge_service_->intent_helper()->AddObserver(this);
 
   if (BluetoothAdapterFactory::IsBluetoothSupported()) {
     VLOG(1) << "Registering bluetooth adapter.";
@@ -501,6 +453,8 @@ ArcBluetoothBridge::~ArcBluetoothBridge() {
   if (bluetooth_adapter_)
     bluetooth_adapter_->RemoveObserver(this);
 
+  arc_bridge_service_->app()->RemoveObserver(this);
+  arc_bridge_service_->intent_helper()->RemoveObserver(this);
   arc_bridge_service_->bluetooth()->SetHost(nullptr);
 }
 
@@ -2473,7 +2427,7 @@ bool ArcBluetoothBridge::IsPowerChangeInitiatedByLocal(
          local_power_changes_.front() == powered;
 }
 
-void ArcBluetoothBridge::MaybeSendInitialPowerChange() {
+void ArcBluetoothBridge::OnConnectionReady() {
   if (!bluetooth_adapter_ || !bluetooth_adapter_->IsPowered()) {
     // The default power state of Bluetooth on Android is off, so there is no
     // need to send an intent to turn off Bluetooth if the initial power state

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.h

@@ -41,9 +41,7 @@ class BrowserContext;
 namespace arc {
 
 namespace mojom {
-class AppHost;
 class AppInstance;
-class IntentHelperHost;
 class IntentHelperInstance;
 }  // namespace mojom
 
@@ -54,6 +52,8 @@ class ArcBluetoothBridge
       public device::BluetoothAdapter::Observer,
       public device::BluetoothAdapterFactory::AdapterCallback,
       public device::BluetoothLocalGattService::Delegate,
+      public ConnectionObserver<mojom::AppInstance>,
+      public ConnectionObserver<mojom::IntentHelperInstance>,
       public mojom::BluetoothHost {
  public:
   using GattStatusCallback =
@@ -341,9 +341,6 @@ class ArcBluetoothBridge
   void StartDiscoveryImpl(bool le_scan);
   void CancelDiscoveryImpl();
 
-  template <typename InstanceType, typename HostType>
-  class ConnectionObserverImpl;
-
   // Power state change on Bluetooth adapter.
   enum class AdapterPowerState { TURN_OFF, TURN_ON };
 
@@ -393,8 +390,9 @@ class ArcBluetoothBridge
   bool IsPowerChangeInitiatedByLocal(
       ArcBluetoothBridge::AdapterPowerState powered) const;
 
-  // Sends initial power state when all preconditions are met.
-  void MaybeSendInitialPowerChange();
+  // ConnectionObserver<mojom::AppInstance>:
+  // ConnectionObserver<mojom::IntentHelperInstance>:
+  void OnConnectionReady() override;
 
   // Manages the powered change intents sent to Android.
   void EnqueueLocalPowerChange(AdapterPowerState powered);
@@ -574,12 +572,6 @@ class ArcBluetoothBridge
   // Timer to turn adapter discoverable off.
   base::OneShotTimer discoverable_off_timer_;
 
-  // Observers to listen the start-up of App and Intent Helper.
-  std::unique_ptr<ConnectionObserverImpl<mojom::AppInstance, mojom::AppHost>>
-      app_observer_;
-  std::unique_ptr<ConnectionObserverImpl<mojom::IntentHelperInstance,
-                                         mojom::IntentHelperHost>>
-      intent_helper_observer_;
   // Queue to track the powered state changes initiated by Android.
   base::queue<AdapterPowerState> remote_power_changes_;
   // Queue to track the powered state changes initiated by Chrome.