Minimize black screen during the boot with multi displays

chromeos/display/output_configurator.h

 // 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.
 
 #ifndef CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_
 #define CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 53 matching lines @@
 
   OutputConfigurator();
   virtual ~OutputConfigurator();
 
   int connected_output_count() const { return connected_output_count_; }
 
   OutputState output_state() const { return output_state_; }
 
   // Initialization, must be called right after constructor.
   // |is_panel_fitting_enabled| indicates hardware panel fitting support.
-  void Init(bool is_panel_fitting_enabled);
+  // If |background_color_argb| is non zero and there are multiple displays,
+  // OutputConfigurator sets the background color of X's RootWindow to this
+  // color.
+  void Init(bool is_panel_fitting_enabled, uint32 background_color_argb);
 
   // Called when the user hits ctrl-F4 to request a display mode change.
   // This method should only return false if it was called in a single-head or
   // headless mode.
   bool CycleDisplayMode();
 
   // 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.
   bool ScreenPowerSet(bool power_on, bool all_displays);
@@ skipping 124 matching lines @@
 
   // Indicates the time at which |output_state_| was entered.
   base::TimeTicks last_enter_state_time_;
 
   DISALLOW_COPY_AND_ASSIGN(OutputConfigurator);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_