Add presubmit check for scoped_ptr usage.

ui/ozone/public/surface_factory_ozone.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/ozone/public/surface_factory_ozone.h"
 
 #include <stdlib.h>
 
 #include "base/command_line.h"
 #include "ui/ozone/public/native_pixmap.h"
@@ skipping 24 matching lines @@
   return 0;
 }
 
 int SurfaceFactoryOzone::GetDrmFd() {
   return -1;
 }
 
 scoped_ptr<SurfaceOzoneEGL> SurfaceFactoryOzone::CreateEGLSurfaceForWidget(
     gfx::AcceleratedWidget widget) {
   NOTIMPLEMENTED();
-  return scoped_ptr<SurfaceOzoneEGL>();
+  return nullptr;
 }
 
 scoped_ptr<SurfaceOzoneEGL>
 SurfaceFactoryOzone::CreateSurfacelessEGLSurfaceForWidget(
     gfx::AcceleratedWidget widget) {
   NOTIMPLEMENTED();
-  return scoped_ptr<SurfaceOzoneEGL>();
+  return nullptr;
 }
 
 scoped_ptr<SurfaceOzoneCanvas> SurfaceFactoryOzone::CreateCanvasForWidget(
     gfx::AcceleratedWidget widget) {
   NOTIMPLEMENTED();
-  return scoped_ptr<SurfaceOzoneCanvas>();
+  return nullptr;
 }
 
 const int32* SurfaceFactoryOzone::GetEGLSurfaceProperties(
     const int32* desired_attributes) {
   return desired_attributes;
 }
 
 ui::OverlayCandidatesOzone* SurfaceFactoryOzone::GetOverlayCandidates(
     gfx::AcceleratedWidget w) {
   return NULL;
@@ skipping 19 matching lines @@
 
 bool SurfaceFactoryOzone::CanShowPrimaryPlaneAsOverlay() {
   return false;
 }
 
 bool SurfaceFactoryOzone::CanCreateNativePixmap(BufferUsage usage) {
   return false;
 }
 
 }  // namespace ui