ash: Make wm::WindowState's c'tor private.

ash/wm/window_state.h

 // Copyright 2013 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_STATE_H_
 #define ASH_WM_WINDOW_STATE_H_
 
 #include "ash/ash_export.h"
 #include "ash/wm/drag_details.h"
 #include "ash/wm/wm_types.h"
@@ skipping 59 matching lines @@
 
     // Gets called before the state objects gets deactivated / detached from the
     // window, so that it can save the various states it is interested in.
     // Note: This only gets called when the state object gets changed.
     virtual void DetachState(WindowState* window_state) = 0;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(State);
   };
 
-  explicit WindowState(aura::Window* window);
+  // Call GetWindowState() to instantiate this class.
   virtual ~WindowState();
 
   aura::Window* window() { return window_; }
   const aura::Window* window() const { return window_; }
 
   bool HasDelegate() const;
   void SetDelegate(scoped_ptr<WindowStateDelegate> delegate);
 
   // Returns the window's current ash state type.
   // Refer to WindowStateType definition in wm_types.h as for why Ash
@@ skipping 206 matching lines @@
   DragDetails* drag_details() { return drag_details_.get(); }
 
   // aura::WindowObserver overrides:
   virtual void OnWindowPropertyChanged(aura::Window* window,
                                        const void* key,
                                        intptr_t old) OVERRIDE;
 
  private:
   friend class DefaultState;
   friend class ash::MaximizeModeWindowState;
+  friend ASH_EXPORT WindowState* GetWindowState(aura::Window*);
   FRIEND_TEST_ALL_PREFIXES(WindowAnimationsTest, CrossFadeToBounds);
 
+  explicit WindowState(aura::Window* window);
+
   WindowStateDelegate* delegate() { return delegate_.get(); }
 
   // Returns the window's current show state.
   ui::WindowShowState GetShowState() const;
 
   // Sets the window's bounds in screen coordinates.
   void SetBoundsInScreen(const gfx::Rect& bounds_in_screen);
 
   // Adjusts the |bounds| so that they are flush with the edge of the
   // workspace if the window represented by |window_state| is side snapped.
@@ skipping 64 matching lines @@
 ASH_EXPORT WindowState* GetWindowState(aura::Window* window);
 
 // const version of GetWindowState.
 ASH_EXPORT const WindowState*
 GetWindowState(const aura::Window* window);
 
 }  // namespace wm
 }  // namespace ash
 
 #endif  // ASH_WM_WINDOW_STATE_H_