Fix race in BrowserAccessibilityManagerWin creation.

content/browser/renderer_host/legacy_render_widget_host_win.h

 // Copyright (c) 2014 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 CONTENT_BROWSER_RENDERER_HOST_LEGACY_RENDER_WIDGET_HOST_WIN_H_
 #define CONTENT_BROWSER_RENDERER_HOST_LEGACY_RENDER_WIDGET_HOST_WIN_H_
 
 #include <atlbase.h>
 #include <atlwin.h>
 #include <atlcrack.h>
@@ skipping 89 matching lines @@
 
   void OnManagerDeleted();
 
   // Functions to show and hide the window.
   void Show();
   void Hide();
 
   // Resizes the window to the bounds passed in.
   void SetBounds(const gfx::Rect& bounds);
 
- protected:
-  virtual void OnFinalMessage(HWND hwnd) OVERRIDE;
-
  private:
   LegacyRenderWidgetHostHWND(HWND parent);
 
   bool Init();
 
   // Returns the target to which the windows input events are forwarded.
   static ui::WindowEventTarget* GetWindowEventTarget(HWND parent);
 
   LRESULT OnEraseBkGnd(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnGetObject(UINT message, WPARAM w_param, LPARAM l_param);
@@ skipping 19 matching lines @@
   // Set to true if we turned on mouse tracking.
   bool mouse_tracking_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(LegacyRenderWidgetHostHWND);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_LEGACY_RENDER_WIDGET_HOST_WIN_H_