Unified Desktop: hook up ash to allow unified desktop mode

ash/display/root_window_transformers.h

Index: ash/display/root_window_transformers.h
diff --git a/ash/display/root_window_transformers.h b/ash/display/root_window_transformers.h
index b41ccdfc3d3691c2512ecb2cd4ecd98d073c363c..61ccea7f7a622505a8cdc17c3567eaba9ed07be4 100644
--- a/ash/display/root_window_transformers.h
+++ b/ash/display/root_window_transformers.h
@@ -13,6 +13,7 @@ class Window;
 
 namespace gfx {
 class Display;
+class Rect;
 class Transform;
 }
 
@@ -32,6 +33,13 @@ ASH_EXPORT RootWindowTransformer* CreateRootWindowTransformerForMirroredDisplay(
     const DisplayInfo& source_display_info,
     const DisplayInfo& mirror_display_info);
 
+// Creates a RootWindowTransformers for unified desktop mode.
+// |screen_bounds| specifies the unified desktop's bounds and
+// |display| specifies the display used to mirror the unified desktop.
+ASH_EXPORT RootWindowTransformer* CreateRootWindowTransformerForUnifiedDesktop(
+    const gfx::Rect& screen_bounds,
+    const gfx::Display& display);
+
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_ROOT_WINDOW_TRANSFORMERS_H_