Factor common code into native_viewport_controller.cc

mojo/services/native_viewport/native_viewport_stub.cc

Index: mojo/services/native_viewport/native_viewport_stub.cc
diff --git a/mojo/services/native_viewport/native_viewport_stub.cc b/mojo/services/native_viewport/native_viewport_stub.cc
index d5b38f2209711a8b97b0f08923bbcd06528c22dd..c7449e10fb48cbf28c22f1c51b77c24e72977c36 100644
--- a/mojo/services/native_viewport/native_viewport_stub.cc
+++ b/mojo/services/native_viewport/native_viewport_stub.cc
@@ -12,7 +12,7 @@ namespace services {
 class NativeViewportStub : public NativeViewport {
  public:
   NativeViewportStub(NativeViewportDelegate* delegate)
-      : delegate_(delegate) {
+      : NativeViewport(delegate) {
   }
   virtual ~NativeViewportStub() {
   }
@@ -23,8 +23,6 @@ class NativeViewportStub : public NativeViewport {
     delegate_->OnDestroyed();
   }
 
-  NativeViewportDelegate* delegate_;
-
   DISALLOW_COPY_AND_ASSIGN(NativeViewportStub);
 };