Handles the failures of output state change.

chromeos/display/output_configurator.cc

Index: chromeos/display/output_configurator.cc
diff --git a/chromeos/display/output_configurator.cc b/chromeos/display/output_configurator.cc
index 66a5b17601dbbe6e411cd19e90dd68635b581add..646b374ba3699021e326c23fc27a69a13d149e0f 100644
--- a/chromeos/display/output_configurator.cc
+++ b/chromeos/display/output_configurator.cc
@@ -661,6 +661,9 @@ bool OutputConfigurator::CycleDisplayMode() {
 
   XRRFreeScreenResources(screen);
   XUngrabServer(display);
+
+  if (!did_change)
+    FOR_EACH_OBSERVER(Observer, observers_, OnDisplayModeChangeFailed());
   return did_change;
 }
 
@@ -737,6 +740,9 @@ bool OutputConfigurator::SetDisplayMode(OutputState new_state) {
       output_state_ == STATE_SINGLE)
     return false;
 
+  if (output_state_ == new_state)
+    return true;
+
   Display* display = base::MessagePumpAuraX11::GetDefaultXDisplay();
   CHECK(display != NULL);
   XGrabServer(display);
@@ -758,6 +764,9 @@ bool OutputConfigurator::SetDisplayMode(OutputState new_state) {
 
   XRRFreeScreenResources(screen);
   XUngrabServer(display);
+
+  if (output_state_ != new_state)
+    FOR_EACH_OBSERVER(Observer, observers_, OnDisplayModeChangeFailed());
   return true;
 }