Reland: Fix X11TopmostWindowFinder

ui/base/x/x11_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_BASE_X_X11_UTIL_H_
 #define UI_BASE_X_X11_UTIL_H_
 
 // This file declares utility functions for X11 (Linux only).
 //
 // These functions do not require the Xlib headers to be included (which is why
@@ skipping 77 matching lines @@
                                                XEvent* last_event);
 
 // Hides the host cursor.
 UI_BASE_EXPORT void HideHostCursor();
 
 // Returns an invisible cursor.
 UI_BASE_EXPORT ::Cursor CreateInvisibleCursor();
 
 // These functions do not cache their results --------------------------
 
+// Returns true if the shape extension is supported.
+UI_BASE_EXPORT bool IsShapeExtensionAvailable();
+
 // Get the X window id for the default root window
 UI_BASE_EXPORT XID GetX11RootWindow();
 
 // Returns the user's current desktop.
 bool GetCurrentDesktop(int* desktop);
 
 enum HideTitlebarWhenMaximized {
   SHOW_TITLEBAR_WHEN_MAXIMIZED = 0,
   HIDE_TITLEBAR_WHEN_MAXIMIZED = 1,
 };
@@ skipping 233 matching lines @@
 UI_BASE_EXPORT void ResetXCursorCache();
 
 // Returns the cached XcursorImage for |cursor|.
 UI_BASE_EXPORT const XcursorImage* GetCachedXcursorImage(::Cursor cursor);
 
 }  // namespace test
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_