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..710575eb9ab0f0c6f2d6a866fc7e4865fbce0d44 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);
@@ -744,6 +750,7 @@ bool OutputConfigurator::SetDisplayMode(OutputState new_state) {
   XRRScreenResources* screen = GetScreenResourcesAndRecordUMA(display, window);
   CHECK(screen != NULL);
 
+  bool did_change = false;
   OutputSnapshot outputs[2] = { {0}, {0} };
   connected_output_count_ =
       GetDualOutputs(display, screen, &outputs[0], &outputs[1]);
@@ -754,10 +761,14 @@ bool OutputConfigurator::SetDisplayMode(OutputState new_state) {
                  outputs,
                  connected_output_count_)) {
     output_state_ = new_state;
+    did_change = true;
   }
 
   XRRFreeScreenResources(screen);
   XUngrabServer(display);
+
+  if (!did_change)

[oshima, 2012/10/02 07:53:02]

if (output_state_ != new_state)

[Jun Mukai, 2012/10/02 20:55:00]

Done.

+    FOR_EACH_OBSERVER(Observer, observers_, OnDisplayModeChangeFailed());
   return true;
 }