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

ash/desktop_background/desktop_background_controller.h

Index: ash/desktop_background/desktop_background_controller.h
diff --git a/ash/desktop_background/desktop_background_controller.h b/ash/desktop_background/desktop_background_controller.h
index acdd7cf760d48bbd73ed3b15da073f4fbbe3b505..9b7069d7b1a61beef8fc0371af3ea9093a66e5f0 100644
--- a/ash/desktop_background/desktop_background_controller.h
+++ b/ash/desktop_background/desktop_background_controller.h
@@ -90,6 +90,13 @@ class ASH_EXPORT DesktopBackgroundController {
   // 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;
@@ -108,6 +115,11 @@ class ASH_EXPORT DesktopBackgroundController {
   // 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_;