Add unittests for X11TopmostWindowFinder

ui/views/widget/desktop_aura/x11_topmost_window_finder.h

 // Copyright 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 UI_VIEWS_WIDGET_DESKTOP_AURA_X11_TOPMOST_WINDOW_FINDER_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_X11_TOPMOST_WINDOW_FINDER_H_
 
+#include <map>
 #include <set>
 
 #include "ui/base/x/x11_util.h"
 #include "ui/gfx/point.h"
 #include "ui/views/views_export.h"
 
 namespace aura {
 class Window;
 }
 
@@ skipping 12 matching lines @@
   aura::Window* FindLocalProcessWindowAt(const gfx::Point& screen_loc,
                                          const std::set<aura::Window*>& ignore);
 
   // Returns the topmost window at |screen_loc|.
   XID FindWindowAt(const gfx::Point& screen_loc);
 
  private:
   // ui::EnumerateWindowsDelegate:
   virtual bool ShouldStopIterating(XID xid) OVERRIDE;
 
-  // Returns true if |window| does not not belong to |ignore|, is visible and
-  // contains |screen_loc_|.
-  bool ShouldStopIteratingAtLocalProcessWindow(aura::Window* window);
+  gfx::Point screen_loc_;
+  XID toplevel_;
 
-  gfx::Point screen_loc_;
-  std::set<aura::Window*> ignore_;
-  XID toplevel_;
+  // Cache of XID to whether the window contains |screen_loc_|. Used to avoid
+  // querying a window's properties multiple times.
+  std::map<XID, bool> cache_;
 
   DISALLOW_COPY_AND_ASSIGN(X11TopmostWindowFinder);
 };
 
 }  // namespace
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_X11_TOPMOST_WINDOW_FINDER_H_