Add presubmit check for scoped_ptr usage.

ui/ozone/public/surface_factory_ozone.cc

Index: ui/ozone/public/surface_factory_ozone.cc
diff --git a/ui/ozone/public/surface_factory_ozone.cc b/ui/ozone/public/surface_factory_ozone.cc
index 3d0f5cab1098abe6ef4a0bb8ddebf20d46ba6ced..1c57038d32452d9eecc4bea34178b9b65e8265af 100644
--- a/ui/ozone/public/surface_factory_ozone.cc
+++ b/ui/ozone/public/surface_factory_ozone.cc
@@ -42,20 +42,20 @@ int SurfaceFactoryOzone::GetDrmFd() {
 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(