Revert of arc: Use the new InstanceHolder for unittests

components/arc/test/fake_notifications_instance.h

Index: components/arc/test/fake_notifications_instance.h
diff --git a/components/arc/test/fake_notifications_instance.h b/components/arc/test/fake_notifications_instance.h
index 1cc91802cf67064d46469ca5243ced0e5b937e32..88f68c06d3e38f8e67fe299412057928034b6f21 100644
--- a/components/arc/test/fake_notifications_instance.h
+++ b/components/arc/test/fake_notifications_instance.h
@@ -4,9 +4,6 @@
 
 #ifndef COMPONENTS_ARC_TEST_FAKE_NOTIFICATIONS_INSTANCE_H_
 #define COMPONENTS_ARC_TEST_FAKE_NOTIFICATIONS_INSTANCE_H_
-
-#include <utility>
-#include <vector>
 
 #include "components/arc/common/notifications.mojom.h"
 #include "components/arc/test/fake_arc_bridge_instance.h"
@@ -15,7 +12,8 @@
 
 class FakeNotificationsInstance : public mojom::NotificationsInstance {
  public:
-  FakeNotificationsInstance();
+  FakeNotificationsInstance(
+      mojo::InterfaceRequest<mojom::NotificationsInstance> request);
   ~FakeNotificationsInstance() override;
 
   void Init(mojom::NotificationsHostPtr host_ptr) override;
@@ -27,8 +25,12 @@
   const std::vector<std::pair<mojo::String, mojom::ArcNotificationEvent>>&
   events() const;
 
+  void WaitForIncomingMethodCall();
+
  private:
   std::vector<std::pair<mojo::String, mojom::ArcNotificationEvent>> events_;
+
+  mojo::Binding<mojom::NotificationsInstance> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeNotificationsInstance);
 };