app_shell: Add support for mouse cursors.

ash/wm/ash_native_cursor_manager.h

Index: ash/wm/ash_native_cursor_manager.h
diff --git a/ash/wm/ash_native_cursor_manager.h b/ash/wm/ash_native_cursor_manager.h
index 80ecc8ef3c3c54fbbca387bc8a598469e628a14b..290b701b30bb739a9045e85ad3d2bb558bfb3303 100644
--- a/ash/wm/ash_native_cursor_manager.h
+++ b/ash/wm/ash_native_cursor_manager.h
@@ -15,14 +15,16 @@
 #include "ui/wm/core/native_cursor_manager.h"
 #include "ui/wm/core/native_cursor_manager_delegate.h"
 
+namespace ui {
+class ImageCursors;
+}
+
 namespace ash {
 
 namespace test {
 class CursorManagerTestApi;
 }
 
-class ImageCursors;
-
 // This does the ash-specific setting of cursor details like cursor
 // visibility. It communicates back with the CursorManager through the
 // NativeCursorManagerDelegate interface, which receives messages about what
@@ -64,7 +66,7 @@ class ASH_EXPORT AshNativeCursorManager
 
   bool native_cursor_enabled_;
 
-  scoped_ptr<ImageCursors> image_cursors_;
+  scoped_ptr<ui::ImageCursors> image_cursors_;
 
   DISALLOW_COPY_AND_ASSIGN(AshNativeCursorManager);
 };