Revert of arc: Use the new InstanceHolder for unittests

components/arc/test/fake_notifications_instance.cc

Index: components/arc/test/fake_notifications_instance.cc
diff --git a/components/arc/test/fake_notifications_instance.cc b/components/arc/test/fake_notifications_instance.cc
index 070cb68370874327fc4a8ec5093747f57c24988e..007ae0b0fe285c34b8cb1bcec1cee42314280c1e 100644
--- a/components/arc/test/fake_notifications_instance.cc
+++ b/components/arc/test/fake_notifications_instance.cc
@@ -6,8 +6,11 @@
 
 namespace arc {
 
-FakeNotificationsInstance::FakeNotificationsInstance() = default;
-FakeNotificationsInstance::~FakeNotificationsInstance() = default;
+FakeNotificationsInstance::FakeNotificationsInstance(
+    mojo::InterfaceRequest<mojom::NotificationsInstance> request)
+    : binding_(this, std::move(request)) {}
+
+FakeNotificationsInstance::~FakeNotificationsInstance() {}
 
 void FakeNotificationsInstance::SendNotificationEventToAndroid(
     const mojo::String& key,
@@ -22,4 +25,8 @@
   return events_;
 }
 
+void FakeNotificationsInstance::WaitForIncomingMethodCall() {
+  binding_.WaitForIncomingMethodCall();
+}
+
 }  // namespace arc