Reland of arc: Use the new InstanceHolder for unittests

components/arc/test/fake_app_instance.h

Index: components/arc/test/fake_app_instance.h
diff --git a/components/arc/test/fake_app_instance.h b/components/arc/test/fake_app_instance.h
index fc1c956b1c303f16f775be3c49c02669de9eecd6..c9394ebb1b1f5a88426ad01cb8fc1f2dae910c75 100644
--- a/components/arc/test/fake_app_instance.h
+++ b/components/arc/test/fake_app_instance.h
@@ -80,10 +80,6 @@ class FakeAppInstance : public mojom::AppInstance {
   explicit FakeAppInstance(mojom::AppHost* app_host);
   ~FakeAppInstance() override;
 
-  void Bind(mojo::InterfaceRequest<mojom::AppInstance> interface_request) {
-    binding_.Bind(std::move(interface_request));
-  }
-
   // mojom::AppInstance overrides:
   void Init(mojom::AppHostPtr host_ptr) override {}
   void RefreshAppList() override;
@@ -153,24 +149,9 @@ class FakeAppInstance : public mojom::AppInstance {
     return shortcut_icon_requests_;
   }
 
-  // This method can be called on tests when a method is intended to
-  // be called across a Mojo proxy.
-  void WaitForIncomingMethodCall();
-
-  // As part of the initialization process, the instance side calls
-  // mojom::AppHost::OnAppInstanceReady(), which in turn calls
-  // mojom::AppInstance::Init() and
-  // mojom::AppInstance::RefreshAppList(). This method should be called after a
-  // call
-  // to mojom::ArcBridgeHost::OnAppInstanceReady() to make sure all method calls
-  // have
-  // been dispatched.
-  void WaitForOnAppInstanceReady();
-
  private:
   using TaskIdToInfo = std::map<int32_t, std::unique_ptr<Request>>;
   // Mojo endpoints.
-  mojo::Binding<mojom::AppInstance> binding_;
   mojom::AppHost* app_host_;
   // Number of RefreshAppList calls.
   int refresh_app_list_count_ = 0;