Enable display rotation, magnifier in unified desktop mode

ash/magnifier/magnification_controller.h

Index: ash/magnifier/magnification_controller.h
diff --git a/ash/magnifier/magnification_controller.h b/ash/magnifier/magnification_controller.h
index ad54c69303c60af6006c0fa87fbfa68dd2562cf5..df896e44a5b894504be6cf9708b3159022b29c61 100644
--- a/ash/magnifier/magnification_controller.h
+++ b/ash/magnifier/magnification_controller.h
@@ -13,7 +13,7 @@
 #include "ui/gfx/geometry/rect.h"
 
 namespace aura {
-class RootWindow;
+class Window;
 }
 
 namespace ash {
@@ -71,6 +71,13 @@ class ASH_EXPORT MagnificationController {
   // This is only used for testing purpose.
   virtual bool IsOnAnimationForTesting() const = 0;
 
+  // Switch Magnified RootWindow to |new_root_window|. This does following:
+  //  - Unzoom the current root_window.
+  //  - Zoom the given new root_window |new_root_window|.
+  //  - Switch the target window from current window to |new_root_window|.
+  virtual void SwitchTargetRootWindow(aura::Window* window,
+                                      bool redraw_original_root) = 0;
+
  protected:
   MagnificationController() {}