chromeos: Save display power state on config failure.

ui/display/chromeos/display_configurator.h

 // Copyright 2014 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.
 
 #ifndef UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_
 #define UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 119 matching lines @@
   // Returns the mode within |display| that matches the given size with highest
   // refresh rate. Returns None if no matching display was found.
   static const DisplayMode* FindDisplayModeMatchingSize(
       const DisplaySnapshot& display,
       const gfx::Size& size);
 
   DisplayConfigurator();
   virtual ~DisplayConfigurator();
 
   MultipleDisplayState display_state() const { return display_state_; }
-  chromeos::DisplayPowerState power_state() const { return power_state_; }
+  chromeos::DisplayPowerState requested_power_state() const {
+    return requested_power_state_;
+  }
   const gfx::Size framebuffer_size() const { return framebuffer_size_; }
   const std::vector<DisplayState>& cached_displays() const {
     return cached_displays_;
   }
 
   void set_state_controller(StateController* controller) {
     state_controller_ = controller;
   }
   void set_mirroring_controller(SoftwareMirroringController* controller) {
     mirroring_controller_ = controller;
@@ skipping 16 matching lines @@
   // DisplayConfigurator sets the background color of X's RootWindow to this
   // color.
   void ForceInitialConfigure(uint32_t background_color_argb);
 
   // Stop handling display configuration events/requests.
   void PrepareForExit();
 
   // Called when powerd notifies us that some set of displays should be turned
   // on or off.  This requires enabling or disabling the CRTC associated with
   // the display(s) in question so that the low power state is engaged.
-  // |flags| contains bitwise-or-ed kSetDisplayPower* values.
+  // |flags| contains bitwise-or-ed kSetDisplayPower* values. Returns true if
+  // the system successfully enters (or was already in) |power_state|.
   bool SetDisplayPower(chromeos::DisplayPowerState power_state, int flags);
 
   // Force switching the display mode to |new_state|. Returns false if
   // switching failed (possibly because |new_state| is invalid for the
   // current set of connected displays).
   bool SetDisplayMode(MultipleDisplayState new_state);
 
   // NativeDisplayDelegate::Observer overrides:
   virtual void OnConfigurationChanged() OVERRIDE;
 
@@ skipping 125 matching lines @@
   // Xrandr X11 extension is supported.
   // If this flag is set to false, any attempts to change the display
   // configuration to immediately fail without changing the state.
   bool configure_display_;
 
   // The current display state.
   MultipleDisplayState display_state_;
 
   gfx::Size framebuffer_size_;
 
-  // The current power state.
-  chromeos::DisplayPowerState power_state_;
+  // The last-requested and current power state. These may differ if
+  // configuration fails: SetDisplayMode() needs the last-requested state while
+  // SetDisplayPower() needs the current state.
+  chromeos::DisplayPowerState requested_power_state_;
+  chromeos::DisplayPowerState current_power_state_;
 
   // Most-recently-used display configuration. Note that the actual
   // configuration changes asynchronously.
   DisplayStateList cached_displays_;
 
   ObserverList<Observer> observers_;
 
   // The timer to delay configuring displays. This is used to aggregate multiple
   // display configuration events when they are reported in short time spans.
   // See comment for NativeDisplayEventDispatcherX11 for more details.
   base::OneShotTimer<DisplayConfigurator> configure_timer_;
 
   // Id for next display protection client.
   ContentProtectionClientId next_display_protection_client_id_;
 
   // Display protection requests of each client.
   ProtectionRequests client_protection_requests_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayConfigurator);
 };
 
 }  // namespace ui
 
 #endif  // UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_