chromeos: Notify observers after display power changes.

chromeos/display/output_configurator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromeos/display/output_configurator.h"
 
 #include <X11/Xlib.h>
 #include <X11/extensions/Xrandr.h>
 #include <X11/extensions/XInput2.h>
 
@@ skipping 224 matching lines @@
 
   VLOG(1) << "SetDisplayPower: power_state="
           << DisplayPowerStateToString(power_state) << " flags=" << flags;
   if (power_state == power_state_ && !(flags & kSetDisplayPowerForceProbe))
     return true;
 
   delegate_->GrabServer();
   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;
 }
 
 bool OutputConfigurator::SetDisplayMode(OutputState new_state) {
   if (!configure_display_)
     return false;
 
   VLOG(1) << "SetDisplayMode: state=" << OutputStateToString(new_state);
   if (output_state_ == new_state) {
     // Cancel software mirroring if the state is moving from
@@ skipping 417 matching lines @@
   float width_ratio = static_cast<float>(mirror_mode_info->width) /
       static_cast<float>(native_mode_info->width);
   float height_ratio = static_cast<float>(mirror_mode_info->height) /
       static_cast<float>(native_mode_info->height);
 
   area_ratio = width_ratio * height_ratio;
   return area_ratio;
 }
 
 }  // namespace chromeos