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 ac6fa0d41e57b1f997fdc8e094a02d66ea2d9504..e5f765ba032618df177fb404df5d07eaf938f239 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"
@@ -275,7 +277,7 @@ 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();
@@ -298,4 +300,6 @@ void DisplayChangeObserver::OnInputDeviceConfigurationChanged() {
   display_manager->OnNativeDisplaysChanged(display_infos);
 }
 
+void DisplayChangeObserver::OnKeyboardDeviceConfigurationChanged() {}
+
 }  // namespace ash