Remove windows/mac/ios specific code from //ui

ui/gfx/win/hwnd_util.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 UI_GFX_WIN_HWND_UTIL_H_
-#define UI_GFX_WIN_HWND_UTIL_H_
-
-#include <windows.h>
-
-#include "base/strings/string16.h"
-#include "ui/gfx/gfx_export.h"
-
-namespace gfx {
-class Point;
-class Size;
-
-// A version of the GetClassNameW API that returns the class name in an
-// base::string16. An empty result indicates a failure to get the class name.
-GFX_EXPORT base::string16 GetClassName(HWND hwnd);
-
-// Useful for subclassing a HWND.  Returns the previous window procedure.
-GFX_EXPORT WNDPROC SetWindowProc(HWND hwnd, WNDPROC wndproc);
-
-// Pointer-friendly wrappers around Get/SetWindowLong(..., GWLP_USERDATA, ...)
-// Returns the previously set value.
-GFX_EXPORT void* SetWindowUserData(HWND hwnd, void* user_data);
-GFX_EXPORT void* GetWindowUserData(HWND hwnd);
-
-// Returns true if the specified window is the current active top window or one
-// of its children.
-GFX_EXPORT bool DoesWindowBelongToActiveWindow(HWND window);
-
-// Sizes the window to have a window size of |pref|, then centers the window
-// over |parent|, ensuring the window fits on screen.
-GFX_EXPORT void CenterAndSizeWindow(HWND parent,
-                                    HWND window,
-                                    const gfx::Size& pref);
-
-// If |hwnd| is NULL logs various thing and CHECKs. Invoke right after calling
-// CreateWindow.
-GFX_EXPORT void CheckWindowCreated(HWND hwnd);
-
-// Shows |window|'s system menu (at a specified |point| in screen coordinates).
-GFX_EXPORT void ShowSystemMenu(HWND window);
-GFX_EXPORT void ShowSystemMenuAtPoint(HWND window, const gfx::Point& point);
-
-// Returns the window you can use to parent a top level window.
-// Note that in some cases we create child windows not parented to its final
-// container so in those cases you should pass true in |get_real_hwnd|.
-GFX_EXPORT HWND GetWindowToParentTo(bool get_real_hwnd);
-
-}  // namespace gfx
-
-#endif  // UI_GFX_WIN_HWND_UTIL_H_