Make PointerDeviceObserver use ui::InputDeviceEventObserver on X11

ui/events/devices/device_data_manager.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/events/devices/device_data_manager.h"
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "ui/events/devices/input_device_event_observer.h"
@@ skipping 133 matching lines @@
     return;
   }
   keyboard_devices_ = devices;
   FOR_EACH_OBSERVER(InputDeviceEventObserver,
                     observers_,
                     OnKeyboardDeviceConfigurationChanged());
 }
 
 void DeviceDataManager::OnMouseDevicesUpdated(
     const std::vector<InputDevice>& devices) {
+  if (devices.size() == mouse_devices_.size() &&
+      std::equal(devices.begin(),
+                 devices.end(),
+                 mouse_devices_.begin(),
+                 InputDeviceEquals)) {
+    return;
+  }
+  mouse_devices_ = devices;
   FOR_EACH_OBSERVER(InputDeviceEventObserver,
                     observers_,
                     OnMouseDeviceConfigurationChanged());
 }
 
 void DeviceDataManager::OnTouchpadDevicesUpdated(
     const std::vector<InputDevice>& devices) {
+  if (devices.size() == touchpad_devices_.size() &&
+      std::equal(devices.begin(),
+                 devices.end(),
+                 touchpad_devices_.begin(),
+                 InputDeviceEquals)) {
+    return;
+  }
+  touchpad_devices_ = devices;
   FOR_EACH_OBSERVER(InputDeviceEventObserver,
                     observers_,
                     OnTouchpadDeviceConfigurationChanged());
 }
 
 void DeviceDataManager::AddObserver(InputDeviceEventObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void DeviceDataManager::RemoveObserver(InputDeviceEventObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace ui