Make ui_controls only usable from interactive_ui_tests. This has two benefits:

ash/wm/window_properties.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_WM_WINDOW_PROPERTIES_H_
 #define ASH_WM_WINDOW_PROPERTIES_H_
 
 #include "ash/ash_export.h"
 #include "ash/wm/property_util.h"
 #include "ui/aura/window.h"
 #include "ui/base/ui_base_types.h"
 
 namespace gfx {
 class Rect;
 }
 
-namespace ui_controls {
-class UIControlsAura;
-}
-
 namespace ash {
 class FramePainter;
 namespace internal {
 class AlwaysOnTopController;
 class RootWindowController;
 
 // Shell-specific window property keys.
 
 // Alphabetical sort.
 
@@ skipping 26 matching lines @@
 // window. It is only available for root windows.
 ASH_EXPORT extern const aura::WindowProperty<ash::FramePainter*>* const
     kSoloWindowFramePainterKey;
 
 // If this is set to true, the window stays in the same root window
 // even if the bounds outside of its root window is set.
 // This is exported as it's used in the tests.
 ASH_EXPORT extern const aura::WindowProperty<bool>* const
     kStayInSameRootWindowKey;
 
-// Used to store a ui_controls for each root window.
-extern const aura::WindowProperty<ui_controls::UIControlsAura*>* const
-    kUIControlsKey;
-
 // A property key to remember if a windows position or size was changed by a
 // user.
 ASH_EXPORT extern const aura::WindowProperty<bool>* const
     kUserChangedWindowPositionOrSizeKey;
 
 // A property to remember the window position which was set before the
 // auto window position manager changed the window bounds, so that it can get
 // restored when only this one window gets shown.
 ASH_EXPORT extern const aura::WindowProperty<gfx::Rect*>* const
     kPreAutoManagedWindowBoundsKey;
@@ skipping 16 matching lines @@
 // True if the window is controlled by the workspace manager.
 extern const aura::WindowProperty<bool>* const
     kWindowTrackedByWorkspaceKey;
 
 // Alphabetical sort.
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WINDOW_PROPERTIES_H_