x11: Use scoped_ptr<> for X11 objects where it makes sense.

ash/wm/maximize_mode/scoped_disable_internal_mouse_and_keyboard_x11.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 "ash/wm/maximize_mode/scoped_disable_internal_mouse_and_keyboard_x11.h"
 
 #include <set>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xlib.h>
 
@@ skipping 58 matching lines @@
     ScopedDisableInternalMouseAndKeyboardX11()
     : touchpad_device_id_(kDeviceIdNone),
       keyboard_device_id_(kDeviceIdNone),
       core_keyboard_device_id_(kDeviceIdNone),
       last_mouse_location_(GetMouseLocationInScreen()) {
 
   ui::DeviceDataManagerX11* device_data_manager =
       static_cast<ui::DeviceDataManagerX11*>(
           ui::DeviceDataManager::GetInstance());
   if (device_data_manager->IsXInput2Available()) {
-    XIDeviceList xi_dev_list = ui::DeviceListCacheX11::GetInstance()->
-        GetXI2DeviceList(gfx::GetXDisplay());
+    const XIDeviceList& xi_dev_list =
+        ui::DeviceListCacheX11::GetInstance()->GetXI2DeviceList(
+            gfx::GetXDisplay());
     for (int i = 0; i < xi_dev_list.count; ++i) {
       std::string device_name(xi_dev_list[i].name);
       base::TrimWhitespaceASCII(device_name, base::TRIM_TRAILING, &device_name);
       if (device_name == kInternalTouchpadName) {
         touchpad_device_id_ = xi_dev_list[i].deviceid;
         device_data_manager->DisableDevice(touchpad_device_id_);
         aura::client::GetCursorClient(
             Shell::GetInstance()->GetPrimaryRootWindow())->HideCursor();
       } else if (device_name == kInternalKeyboardName) {
         keyboard_device_id_ = xi_dev_list[i].deviceid;
@@ skipping 55 matching lines @@
     // blocked. Move the mouse cursor back to its last known location resulting
     // from an external mouse to prevent the internal touchpad from moving it.
     SetMouseLocationInScreen(last_mouse_location_);
   } else {
     // Track the last location seen from an external mouse event.
     last_mouse_location_ = GetMouseLocationInScreen();
   }
 }
 
 }  // namespace ash