Make SetDisplayPower() take a callback to signal completion

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 22 matching lines @@
 class DisplaySnapshot;
 class NativeDisplayDelegate;
 class UpdateDisplayConfigurationTask;
 
 // This class interacts directly with the system display configurator.
 class DISPLAY_EXPORT DisplayConfigurator : public NativeDisplayObserver {
  public:
   typedef uint64_t ContentProtectionClientId;
   static const ContentProtectionClientId kInvalidClientId = 0;
 
+  typedef base::Callback<void(bool)> ConfigurationCallback;
+
   struct DisplayState {
     DisplayState();
 
     DisplaySnapshot* display;  // Not owned.
 
     // User-selected mode for the display.
     const DisplayMode* selected_mode;
 
     // Mode used when displaying the same desktop on multiple displays.
     const DisplayMode* mirror_mode;
@@ skipping 162 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. Returns true if
-  // the system successfully enters (or was already in) |power_state|.
-  void SetDisplayPower(chromeos::DisplayPowerState power_state, int flags);
+  // |flags| contains bitwise-or-ed kSetDisplayPower* values. After the
+  // configuration finishes |callback| is called with the status of the
+  // operation.
+  void SetDisplayPower(chromeos::DisplayPowerState power_state,
+                       int flags,
+                       const ConfigurationCallback& callback);
 
   // 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).
   void SetDisplayMode(MultipleDisplayState new_state);
 
   // NativeDisplayDelegate::Observer overrides:
   void OnConfigurationChanged() override;
 
   void AddObserver(Observer* observer);
@@ skipping 89 matching lines @@
                     const std::vector<DisplayState>& displays,
                     const gfx::Size& framebuffer_size,
                     MultipleDisplayState new_display_state,
                     chromeos::DisplayPowerState new_power_state);
 
   // Helps in identifying if a configuration task needs to be scheduled.
   // Return true if any of the |requested_*| parameters have been updated. False
   // otherwise.
   bool ShouldRunConfigurationTask() const;
 
+  // Helper functions which will call the callbacks in
+  // |pending_configuration_callbacks_| and |queued_configuration_callbacks_|
+  // and clear the lists after. |success| is the configuration status used when
+  // calling the callbacks.
+  void CallAndClearPendingCallbacks(bool success);
+  void CallAndClearQueuedCallbacks(bool success);
+
   StateController* state_controller_;
   SoftwareMirroringController* mirroring_controller_;
   scoped_ptr<NativeDisplayDelegate> native_display_delegate_;
 
   // Used to enable modes which rely on panel fitting.
   bool is_panel_fitting_enabled_;
 
   // This is detected by the constructor to determine whether or not we should
   // be enabled.  If we aren't running on ChromeOS, we can't assume that the
   // Xrandr X11 extension is supported.
@@ skipping 13 matching lines @@
 
   // Stores the requested power state.
   chromeos::DisplayPowerState requested_power_state_;
 
   // True if |requested_power_state_| has been changed due to a user request.
   bool requested_power_state_change_;
 
   // Bitwise-or value of the |kSetDisplayPower*| flags defined above.
   int requested_power_flags_;
 
+  // List of callbacks from callers waiting for the display configuration to
+  // start/finish. Note these callbacks belong to pending request not a

[Daniel Erat, 2015/01/30 17:14:07]

the use of "pending" here is pretty confusing given the
|pending_configuration_callbacks_| member. :-) maybe rename
|pending_configuration_callbacks_| to |active_configuration_callbacks_| or
|in_progress_configuration_callbacks_| to make the distinction clearer?

also nit: add comma after "request"

[dnicoara, 2015/01/30 18:25:28]

Done.

+  // request currently active.
+  std::vector<ConfigurationCallback> queued_configuration_callbacks_;
+
+  // List of callbacks belonging to the currently running display configuration
+  // task.
+  std::vector<ConfigurationCallback> pending_configuration_callbacks_;
+
   // True if the caller wants to force the display configuration process.
   bool force_configure_;
 
   // Most-recently-used display configuration. Note that the actual
   // configuration changes asynchronously.
   DisplayStateList cached_displays_;
 
   // Most-recently-used framebuffer size.
   gfx::Size framebuffer_size_;
 
@@ skipping 19 matching lines @@
 
   // This must be the last variable.
   base::WeakPtrFactory<DisplayConfigurator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayConfigurator);
 };
 
 }  // namespace ui
 
 #endif  // UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_