Adds special support to the device manager for keyboards devices.

ui/events/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/device_data_manager.h"
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "ui/events/input_device_event_observer.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/point3_f.h"
 
 namespace ui {
 
+namespace {
+
+bool TouchscreenEquals(const ui::TouchscreenDevice& a,
+    const ui::TouchscreenDevice& b) {
+  return a.id == b.id;
+}
+
+bool KeyboardEquals(const ui::KeyboardDevice& a,
+    const ui::KeyboardDevice& b) {
+  return a.id == b.id;
+}
+
+}  // namespace
+
 // static
 DeviceDataManager* DeviceDataManager::instance_ = NULL;
 
 DeviceDataManager::DeviceDataManager() {
   CHECK(!instance_) << "Can not create multiple instances of DeviceDataManager";
   instance_ = this;
 
   base::AtExitManager::RegisterTask(
       base::Bind(&base::DeletePointer<DeviceDataManager>, this));
 
@@ skipping 78 matching lines @@
 }
 
 int64_t DeviceDataManager::GetDisplayForTouchDevice(int touch_device_id) const {
   if (IsTouchDeviceIdValid(touch_device_id))
     return touch_device_to_display_map_[touch_device_id];
   return gfx::Display::kInvalidDisplayID;
 }
 
 void DeviceDataManager::OnTouchscreenDevicesUpdated(
     const std::vector<TouchscreenDevice>& devices) {
+  if (devices.size() == touchscreen_devices_.size() &&
+      std::equal(devices.begin(), devices.end(),
+          touchscreen_devices_.begin(), TouchscreenEquals)) {
+    return;
+  }
   touchscreen_devices_ = devices;
+  FOR_EACH_OBSERVER(InputDeviceEventObserver,
+                  observers_,
+                  OnTouchscreenDeviceConfigurationChanged());
+}
 
+void DeviceDataManager::OnKeyboardDevicesUpdated(
+    const std::vector<KeyboardDevice>& devices) {
+  if (devices.size() == keyboard_devices_.size() &&
+      std::equal(devices.begin(), devices.end(),
+          keyboard_devices_.begin(), KeyboardEquals)) {
+    return;
+  }
+  keyboard_devices_ = devices;
   FOR_EACH_OBSERVER(InputDeviceEventObserver,
-                    observers_,
-                    OnInputDeviceConfigurationChanged());
+                  observers_,
+                  OnKeyboardDeviceConfigurationChanged());
 }
 
 void DeviceDataManager::AddObserver(InputDeviceEventObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void DeviceDataManager::RemoveObserver(InputDeviceEventObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace ui