Add presubmit check for scoped_ptr usage.

ui/ozone/platform/dri/gbm_surface_factory.cc

 // Copyright 2014 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/platform/dri/gbm_surface_factory.h"
 
 #include <gbm.h>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 116 matching lines @@
   if (!surface->Initialize())
     return nullptr;
 
   return surface.Pass();
 }
 
 scoped_ptr<SurfaceOzoneEGL>
 GbmSurfaceFactory::CreateSurfacelessEGLSurfaceForWidget(
     gfx::AcceleratedWidget widget) {
   if (!allow_surfaceless_)
-    return scoped_ptr<SurfaceOzoneEGL>();
+    return nullptr;
 
   DriWindowDelegate* delegate = GetOrCreateWindowDelegate(widget);
   return scoped_ptr<SurfaceOzoneEGL>(new GbmSurfaceless(delegate));
 }
 
 scoped_refptr<ui::NativePixmap> GbmSurfaceFactory::CreateNativePixmap(
     gfx::AcceleratedWidget widget,
     gfx::Size size,
     BufferFormat format,
     BufferUsage usage) {
@@ skipping 66 matching lines @@
     scoped_ptr<DriWindowDelegate> delegate(new DriWindowDelegateImpl(
         widget, gbm_, window_manager_, screen_manager_));
     delegate->Initialize();
     window_manager_->AddWindowDelegate(widget, delegate.Pass());
   }
 
   return window_manager_->GetWindowDelegate(widget);
 }
 
 }  // namespace ui