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

ui/views/widget/desktop_aura/desktop_screen_x11.cc

Index: ui/views/widget/desktop_aura/desktop_screen_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.cc b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
index 99ca833d9aae81000245f764dfe7a83c6f4d16a5..d9277807d443470b824144ab0ff48af2ccfcadfe 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
@@ -26,6 +26,7 @@
 #include "ui/gfx/x/x11_types.h"
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
+#include "ui/views/widget/desktop_aura/x11_topmost_window_finder.h"
 
 namespace {
 
@@ -64,54 +65,6 @@ std::vector<gfx::Display> GetFallbackDisplayList() {
   return std::vector<gfx::Display>(1, gfx_display);
 }
 
-// Helper class to GetWindowAtScreenPoint() which returns the topmost window at
-// the location passed to FindAt(). NULL is returned if a window which does not
-// belong to Chromium is topmost at the passed in location.
-class ToplevelWindowFinder : public ui::EnumerateWindowsDelegate {
- public:
-  ToplevelWindowFinder() : toplevel_(NULL) {
-  }
-
-  virtual ~ToplevelWindowFinder() {
-  }
-
-  aura::Window* FindAt(const gfx::Point& screen_loc) {
-    screen_loc_ = screen_loc;
-    ui::EnumerateTopLevelWindows(this);
-    return toplevel_;
-  }
-
- protected:
-  virtual bool ShouldStopIterating(XID xid) OVERRIDE {
-   if (!ui::IsWindowVisible(xid))
-     return false;
-
-    aura::Window* window =
-        views::DesktopWindowTreeHostX11::GetContentWindowForXID(xid);
-    if (window) {
-      // Currently |window|->IsVisible() always returns true.
-      // TODO(pkotwicz): Fix this. crbug.com/353038
-      if (window->IsVisible() &&
-          window->GetBoundsInScreen().Contains(screen_loc_)) {
-        toplevel_ = window;
-        return true;
-      }
-      return false;
-    }
-
-    if (ui::WindowContainsPoint(xid, screen_loc_)) {
-      // toplevel_ = NULL
-      return true;
-    }
-    return false;
-  }
-
-  gfx::Point screen_loc_;
-  aura::Window* toplevel_;
-
-  DISALLOW_COPY_AND_ASSIGN(ToplevelWindowFinder);
-};
-
 }  // namespace
 
 namespace views {
@@ -236,8 +189,8 @@ gfx::NativeWindow DesktopScreenX11::GetWindowUnderCursor() {
 
 gfx::NativeWindow DesktopScreenX11::GetWindowAtScreenPoint(
     const gfx::Point& point) {
-  ToplevelWindowFinder finder;
-  return finder.FindAt(point);
+  X11TopmostWindowFinder finder;
+  return finder.FindLocalProcessWindowAt(point, std::set<aura::Window*>());
 }
 
 int DesktopScreenX11::GetNumDisplays() const {