cros: WallpaperController reparent based on session state

ash/wallpaper/wallpaper_controller.h

Index: ash/wallpaper/wallpaper_controller.h
diff --git a/ash/wallpaper/wallpaper_controller.h b/ash/wallpaper/wallpaper_controller.h
index 345f469d306dfd91d4d9b1fd615e60f2a7c8f947..f383f728595b1815e23b96495f65263e91d8da27 100644
--- a/ash/wallpaper/wallpaper_controller.h
+++ b/ash/wallpaper/wallpaper_controller.h
@@ -83,14 +83,6 @@ class ASH_EXPORT WallpaperController
   // crashes. An example test is SystemGestureEventFilterTest.ThreeFingerSwipe.
   void CreateEmptyWallpaper();
 
-  // Move all wallpaper widgets to the locked container.
-  // Returns true if the wallpaper moved.
-  bool MoveToLockedContainer();
-
-  // Move all wallpaper widgets to unlocked container.
-  // Returns true if the wallpaper moved.
-  bool MoveToUnlockedContainer();
-
   // WmDisplayObserver:
   void OnDisplayConfigurationChanged() override;
 
@@ -132,6 +124,9 @@ class ASH_EXPORT WallpaperController
   void OnColorCalculationComplete() override;
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(WallpaperControllerTest, BasicReparenting);
+  FRIEND_TEST_ALL_PREFIXES(WallpaperControllerTest,
+                           WallpaperMovementDuringUnlock);
   friend class WallpaperControllerTest;
 
   // Creates a WallpaperWidgetController for |root_window|.
@@ -165,6 +160,14 @@ class ASH_EXPORT WallpaperController
   // system state (e.g. wallpaper image, SessionState, etc.).
   bool ShouldCalculateColors() const;
 
+  // Move all wallpaper widgets to the locked container.
+  // Returns true if the wallpaper moved.
+  bool MoveToLockedContainer();
+
+  // Move all wallpaper widgets to unlocked container.
+  // Returns true if the wallpaper moved.
+  bool MoveToUnlockedContainer();
+
   bool locked_;
 
   WallpaperMode wallpaper_mode_;