Moves WmWindow::GetInternalWidget() into a standalone function

ash/common/wm_window.h

 // Copyright 2016 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_COMMON_WM_WINDOW_H_
 #define ASH_COMMON_WM_WINDOW_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 20 matching lines @@
 class Transform;
 }
 
 namespace ui {
 class EventHandler;
 class Layer;
 }
 
 namespace views {
 class View;
-class Widget;
 }
 
 namespace ash {
 
 class ImmersiveFullscreenController;
 class RootWindowController;
 class WmLayoutManager;
 class WmShell;
 class WmTransientWindowObserver;
 class WmWindowTestApi;
@@ skipping 220 matching lines @@
   void StackChildAtBottom(WmWindow* child);
   void StackChildAbove(WmWindow* child, WmWindow* target);
   void StackChildBelow(WmWindow* child, WmWindow* target);
 
   void SetAlwaysOnTop(bool value);
   bool IsAlwaysOnTop() const;
 
   void Hide();
   void Show();
 
-  // Returns the widget associated with this window, or null if not associated
-  // with a widget. Only ash system UI widgets are returned, not widgets created
-  // by the mus window manager code to show a non-client frame.
-  views::Widget* GetInternalWidget();
-
   // Requests the window to close and destroy itself. This is intended to
   // forward to an associated widget.
   void CloseWidget();
 
   void SetFocused();
   bool IsFocused() const;
 
   bool IsActive() const;
   void Activate();
   void Deactivate();
@@ skipping 32 matching lines @@
 
   // Returns a View that renders the contents of this window's layers.
   std::unique_ptr<views::View> CreateViewWithRecreatedLayers();
 
   void AddTransientWindowObserver(WmTransientWindowObserver* observer);
   void RemoveTransientWindowObserver(WmTransientWindowObserver* observer);
 
   // Adds or removes a handler to receive events targeted at this window, before
   // this window handles the events itself; the handler does not recieve events
   // from embedded windows. This only supports windows with internal widgets;
-  // see GetInternalWidget(). Ownership of the handler is not transferred.
+  // see ash::GetInternalWidgetForWindow(). Ownership of the handler is not
+  // transferred.
   //
   // Also note that the target of these events is always an aura::Window.
   void AddLimitedPreTargetHandler(ui::EventHandler* handler);
   void RemoveLimitedPreTargetHandler(ui::EventHandler* handler);
 
  private:
   friend class WmWindowTestApi;
 
   explicit WmWindow(aura::Window* window);
 
@@ skipping 22 matching lines @@
 
   // If true the minimum size is 0x0, default is minimum size comes from widget.
   bool use_empty_minimum_size_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(WmWindow);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_WINDOW_H_