2nd display should show the same background as login/lock screen:

ash/desktop_background/desktop_background_controller.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 ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_
 #define ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_
 
 #include "ash/ash_export.h"
 #include "ash/desktop_background/desktop_background_resources.h"
 #include "base/basictypes.h"
@@ skipping 72 matching lines @@
   void SetDesktopBackgroundSolidColorMode(SkColor color);
 
   // Creates an empty wallpaper. Some tests require a wallpaper widget is ready
   // when running. However, the wallpaper widgets are now created asynchronously
   // . If loading a real wallpaper, there are cases that these tests crash
   // because the required widget is not ready. This function synchronously
   // creates an empty widget for those tests to prevent crashes. An example test
   // is SystemGestureEventFilterTest.ThreeFingerSwipe.
   void CreateEmptyWallpaper();
 
+  // Create desktop views on Lock Screen layer.
+  void CreateLockScreenDesktops();
+
+  // Remove all desktop views on Lock Screen layer created by
+  // CreateLockScreenDesktops.
+  void RemoveLockScreenDesktops();
+
  private:
   // An operation to asynchronously loads wallpaper.
   class WallpaperOperation;
 
   struct WallpaperData;
 
   // Creates a new background widget using the current wallpapaer image and
   // use it as a background of the |root_window|. Deletes the old widget if any.
   void SetDesktopBackgroundImage(aura::RootWindow* root_window);
 
   // Update the background of all root windows using the current wallpaper image
   // in |current_wallpaper_|.
   void UpdateDesktopBackgroundImageMode();
 
   // Creates a new background widget and sets the background mode to image mode.
   // Called after wallpaper loaded successfully.
   void OnWallpaperLoadCompleted(scoped_refptr<WallpaperOperation> wo);
 
+  // Add layer with solid |color| to container |container_id| in |root_window|
+  void SetColorLayerForContainer(SkColor color,
+      aura::RootWindow* root_window,
+      int container_id);

[bshe, 2012/07/23 00:19:36]

Nit: Could you make the last two argument align with the first argument?

[Denis Kuznetsov (DE-MUC), 2012/07/23 14:01:09]

Done.

+
   // Can change at runtime.
   BackgroundMode desktop_background_mode_;
 
   SkColor background_color_;
 
   // The current wallpaper.
   scoped_ptr<WallpaperData> current_wallpaper_;
 
   scoped_refptr<WallpaperOperation> wallpaper_op_;
 
   base::WeakPtrFactory<DesktopBackgroundController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopBackgroundController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_