Use StrongBinding instead of InterfaceImpl in wm event dispatcher

services/window_manager/native_viewport_event_dispatcher_impl.h

Index: services/window_manager/native_viewport_event_dispatcher_impl.h
diff --git a/services/window_manager/native_viewport_event_dispatcher_impl.h b/services/window_manager/native_viewport_event_dispatcher_impl.h
index a95821d7ee5ed564f2de5d5de2c855bc661c6bbe..d09160d6e99a93f15306524c9b67faa3da2d84b0 100644
--- a/services/window_manager/native_viewport_event_dispatcher_impl.h
+++ b/services/window_manager/native_viewport_event_dispatcher_impl.h
@@ -6,6 +6,7 @@
 #define SERVICES_WINDOW_MANAGER_NATIVE_VIEWPORT_EVENT_DISPATCHER_IMPL_H_
 
 #include "base/basictypes.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
 #include "mojo/services/native_viewport/public/interfaces/native_viewport.mojom.h"
 #include "ui/events/event_source.h"
 
@@ -15,9 +16,11 @@ class WindowManagerApp;
 
 class NativeViewportEventDispatcherImpl
     : public ui::EventSource,
-      public mojo::InterfaceImpl<mojo::NativeViewportEventDispatcher> {
+      public mojo::NativeViewportEventDispatcher {
  public:
-  explicit NativeViewportEventDispatcherImpl(WindowManagerApp* app);
+  NativeViewportEventDispatcherImpl(
+      WindowManagerApp* app,
+      mojo::InterfaceRequest<mojo::NativeViewportEventDispatcher> request);
   ~NativeViewportEventDispatcherImpl() override;
 
  private:
@@ -30,6 +33,7 @@ class NativeViewportEventDispatcherImpl
 
   WindowManagerApp* app_;
 
+  mojo::StrongBinding<mojo::NativeViewportEventDispatcher> binding_;
   DISALLOW_COPY_AND_ASSIGN(NativeViewportEventDispatcherImpl);
 };