Adds special support to the device manager for keyboards devices.

ui/events/device_data_manager.cc

Index: ui/events/device_data_manager.cc
diff --git a/ui/events/device_data_manager.cc b/ui/events/device_data_manager.cc
index d255b871abc80b10082d7408e92e25deafc7cb9a..4a375af325a201f341379b67d38c73104cdcf721 100644
--- a/ui/events/device_data_manager.cc
+++ b/ui/events/device_data_manager.cc
@@ -13,6 +13,20 @@
 
 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;
 
@@ -111,11 +125,26 @@ int64_t DeviceDataManager::GetDisplayForTouchDevice(int touch_device_id) const {
 
 void DeviceDataManager::OnTouchscreenDevicesUpdated(
     const std::vector<TouchscreenDevice>& devices) {
-  touchscreen_devices_ = devices;
+  if (devices.size() != touchscreen_devices_.size() ||
+      std::equal(devices.begin(), devices.end(),

[flackr, 2014/10/04 00:35:12]

Did you mean !std::equal(...?

[rsadam, 2014/10/04 18:46:27]

Done.

+      touchscreen_devices_.begin(), TouchscreenEquals)) {

[flackr, 2014/10/04 00:35:12]

nit: indent 4 more (to show it's wrapped from std::equal(...
Or line up with devices.begin() after the '(' above.

[rsadam, 2014/10/04 18:46:27]

Done.

+    touchscreen_devices_ = devices;

[flackr, 2014/10/04 00:35:12]

Better yet, early return if the device list looks the same rather than wrapping
the contents of the function in an if.

[rsadam, 2014/10/04 18:46:27]

Done.

+    FOR_EACH_OBSERVER(InputDeviceEventObserver,
+                    observers_,
+                    OnTouchscreenDeviceConfigurationChanged());
+  }
+}
 
-  FOR_EACH_OBSERVER(InputDeviceEventObserver,
+void DeviceDataManager::OnKeyboardDevicesUpdated(
+    const std::vector<KeyboardDevice>& devices) {
+  if (devices.size() != keyboard_devices_.size() ||
+      std::equal(devices.begin(), devices.end(),

[flackr, 2014/10/04 00:35:12]

ditto, !std::equal?

[rsadam, 2014/10/04 18:46:27]

Done.

+      keyboard_devices_.begin(), KeyboardEquals)) {

[flackr, 2014/10/04 00:35:12]

ditto, indent 4 more or to just past '(' above.

[rsadam, 2014/10/04 18:46:27]

Done.

+    keyboard_devices_ = devices;
+    FOR_EACH_OBSERVER(InputDeviceEventObserver,
                     observers_,
-                    OnInputDeviceConfigurationChanged());
+                    OnKeyboardDeviceConfigurationChanged());
+  }
 }
 
 void DeviceDataManager::AddObserver(InputDeviceEventObserver* observer) {