Merge three implementations for getting the topmost x11 window at a point

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 <set>
+
+#include "ui/base/x/x11_util.h"
+#include "ui/gfx/point.h"
+#include "ui/views/views_export.h"
+
+namespace aura {
+class Window;
+}
+
+namespace views {
+
+// Utility class for finding the topmost window at a given screen position.
+class VIEWS_EXPORT X11TopmostWindowFinder
+    : public ui::EnumerateWindowsDelegate {
+ public:
+  X11TopmostWindowFinder();
+  virtual ~X11TopmostWindowFinder();
+
+  // Returns the topmost window at |screen_loc|, ignoring the windows in
+  // |ignore|. Returns NULL if the topmost window at |screen_loc| does not
+  // belong to Chrome.
+  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_;
+  std::set<aura::Window*> ignore_;
+  XID toplevel_;
+
+  DISALLOW_COPY_AND_ASSIGN(X11TopmostWindowFinder);
+};
+
+}  // namespace
+
+#endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_X11_TOPMOST_WINDOW_FINDER_H_