Add unittests for X11TopmostWindowFinder

ui/views/widget/desktop_aura/x11_topmost_window_finder.h

Index: ui/views/widget/desktop_aura/x11_topmost_window_finder.h
diff --git a/ui/views/widget/desktop_aura/x11_topmost_window_finder.h b/ui/views/widget/desktop_aura/x11_topmost_window_finder.h
index cf8498abe50f5a803a5613cb97f3cccda0348b25..9e7856598c69ff95b5e6f82239fd8bc4f7d51d77 100644
--- a/ui/views/widget/desktop_aura/x11_topmost_window_finder.h
+++ b/ui/views/widget/desktop_aura/x11_topmost_window_finder.h
@@ -5,6 +5,7 @@
 #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"
@@ -37,14 +38,13 @@ class VIEWS_EXPORT X11TopmostWindowFinder
   // 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_;
-  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);
 };