Add presubmit check for scoped_ptr usage.

ui/events/x/events_x_unittest.cc

 // Copyright (c) 2012 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 <cstring>
 #include <set>
 
 #include <X11/extensions/XInput2.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
@@ skipping 535 matching lines @@
                           0);
   EXPECT_EQ(ui::ET_KEY_PRESSED, ui::EventTypeFromNative(xev));
   xev.InitGenericKeyEvent(master_device_id,
                           other_device_id,
                           ui::ET_KEY_PRESSED,
                           ui::VKEY_B,
                           0);
   EXPECT_EQ(ui::ET_KEY_PRESSED, ui::EventTypeFromNative(xev));
 
   device_data_manager->EnableDevice(blocked_device_id);
-  device_data_manager->SetDisabledKeyboardAllowedKeys(
-      scoped_ptr<std::set<KeyboardCode> >());
+  device_data_manager->SetDisabledKeyboardAllowedKeys(nullptr);
 
   // A key returns KEY_PRESSED as per usual now that keyboard was re-enabled.
   xev.InitGenericKeyEvent(master_device_id,
                           blocked_device_id,
                           ui::ET_KEY_PRESSED,
                           ui::VKEY_A,
                           0);
   EXPECT_EQ(ui::ET_KEY_PRESSED, ui::EventTypeFromNative(xev));
 }
 
@@ skipping 61 matching lines @@
         KeyEventTestApi test_event(&key_event);
         test_event.set_is_char(true);
       }
       EXPECT_FALSE(key_event.flags() & ui::EF_IME_FABRICATED_KEY);
     }
   }
 }
 #endif
 
 }  // namespace ui