chromeos: Notify observers after display power changes.

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 c8de844520115706277f8a20a5eeae159a3ff983..7aa594d7221196c2c76e87f67709e161d2b277e8 100644
--- a/chromeos/display/output_configurator.cc
+++ b/chromeos/display/output_configurator.cc
@@ -242,20 +242,24 @@ bool OutputConfigurator::SetDisplayPower(DisplayPowerState power_state,
   std::vector<OutputSnapshot> outputs =
       delegate_->GetOutputs(state_controller_);
 
+  bool changed = false;
   bool only_if_single_internal_display =
       flags & kSetDisplayPowerOnlyIfSingleInternalDisplay;
   bool single_internal_display = outputs.size() == 1 && outputs[0].is_internal;
   if ((single_internal_display || !only_if_single_internal_display) &&
       EnterStateOrFallBackToSoftwareMirroring(
           GetOutputState(outputs, power_state), power_state, outputs)) {
-    if (power_state != DISPLAY_POWER_ALL_OFF)  {
-      // Force the DPMS on since the driver doesn't always detect that it
-      // should turn on. This is needed when coming back from idle suspend.
+    // Force the DPMS on since the driver doesn't always detect that it
+    // should turn on. This is needed when coming back from idle suspend.
+    if (power_state != DISPLAY_POWER_ALL_OFF)
       delegate_->ForceDPMSOn();
-    }
+
+    changed = true;
   }
 
   delegate_->UngrabServer();
+  if (changed)
+    NotifyOnDisplayChanged();

[Daniel Erat, 2013/08/16 00:51:46]

I don't think that we need to notify about failures, since power state changes
aren't Chrome-initiated (and only change the DisplayPowerState instead of the
OutputState). Let me know if I'm wrong, though.

   return true;
 }