Adds special support to the device manager for keyboards devices.

ash/display/display_change_observer_chromeos.cc

Index: ash/display/display_change_observer_chromeos.cc
diff --git a/ash/display/display_change_observer_chromeos.cc b/ash/display/display_change_observer_chromeos.cc
index 4065c915fe54d7c324cebad5ca05f106e1091bd4..db5147237525aa5d1c814b7a3dd6e8d31d942cb7 100644
--- a/ash/display/display_change_observer_chromeos.cc
+++ b/ash/display/display_change_observer_chromeos.cc
@@ -7,6 +7,8 @@
 #include <algorithm>
 #include <map>
 #include <set>
+#include <string>
+#include <utility>
 #include <vector>
 
 #include "ash/ash_switches.h"
@@ -273,7 +275,7 @@ float DisplayChangeObserver::FindDeviceScaleFactor(float dpi) {
   return 1.0f;
 }
 
-void DisplayChangeObserver::OnInputDeviceConfigurationChanged() {
+void DisplayChangeObserver::OnTouchscreenDeviceConfigurationChanged() {
   std::vector<DisplayInfo> display_infos;
   DisplayManager* display_manager =
       ash::Shell::GetInstance()->display_manager();
@@ -296,4 +298,6 @@ void DisplayChangeObserver::OnInputDeviceConfigurationChanged() {
   display_manager->OnNativeDisplaysChanged(display_infos);
 }
 
+void DisplayChangeObserver::OnKeyboardDeviceConfigurationChanged() {}
+
 }  // namespace ash