Avoid InterfaceImpl in //services/test_service

services/test_service/test_request_tracker_impl.h

Index: services/test_service/test_request_tracker_impl.h
diff --git a/services/test_service/test_request_tracker_impl.h b/services/test_service/test_request_tracker_impl.h
index 8856dcd1a4c290316dec5b16ffe7c81e3317b597..465d697e6b11ead4dfa7fcf268645fe0b133c3f4 100644
--- a/services/test_service/test_request_tracker_impl.h
+++ b/services/test_service/test_request_tracker_impl.h
@@ -45,10 +45,11 @@ class TestRequestTrackerImpl : public TestRequestTracker {
   MOJO_DISALLOW_COPY_AND_ASSIGN(TestRequestTrackerImpl);
 };
 
-class TestTrackedRequestServiceImpl
-    : public InterfaceImpl<TestTrackedRequestService> {
+class TestTrackedRequestServiceImpl : public TestTrackedRequestService {
  public:
-  explicit TestTrackedRequestServiceImpl(TrackingContext* context);
+  TestTrackedRequestServiceImpl(
+      InterfaceRequest<TestTrackedRequestService> request,
+      TrackingContext* context);
   ~TestTrackedRequestServiceImpl() override;
 
   // |TestTrackedRequestService| implementation.
@@ -57,6 +58,8 @@ class TestTrackedRequestServiceImpl
 
  private:
   TrackingContext* context_;
+  StrongBinding<TestTrackedRequestService> binding_;
+
   MOJO_DISALLOW_COPY_AND_ASSIGN(TestTrackedRequestServiceImpl);
 };