Add unit test for ArcBluetoothBridge and TypeConverter

components/arc/arc_bridge_service.cc

Index: components/arc/arc_bridge_service.cc
diff --git a/components/arc/arc_bridge_service.cc b/components/arc/arc_bridge_service.cc
index 5591e1b94775b45b263bd1f24910793cc8e30c6c..2d3bac2ce84dc3f9bd43696cd7d53589e2a4b56b 100644
--- a/components/arc/arc_bridge_service.cc
+++ b/components/arc/arc_bridge_service.cc
@@ -101,6 +101,14 @@ void ArcBridgeService::RemoveObserver(Observer* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
+mojom::BluetoothInstance* ArcBridgeService::bluetooth_instance() {
+  return bluetooth_ptr_.get();
+}
+
+int32_t ArcBridgeService::bluetooth_version() const {
+  return bluetooth_ptr_.version();
+}
+
 void ArcBridgeService::OnAppInstanceReady(mojom::AppInstancePtr app_ptr) {
   DCHECK(CalledOnValidThread());
   temporary_app_ptr_ = std::move(app_ptr);