gfx: Make conversions from gfx::Point to PointF explicit.

ui/aura/window_tree_host_x11.cc

Index: ui/aura/window_tree_host_x11.cc
diff --git a/ui/aura/window_tree_host_x11.cc b/ui/aura/window_tree_host_x11.cc
index 084296c34086b8ab8e2c9a20912036b04dedf0be..7d950a9e22f8a4c0977149d34b22b22036694034 100644
--- a/ui/aura/window_tree_host_x11.cc
+++ b/ui/aura/window_tree_host_x11.cc
@@ -169,9 +169,9 @@ class TouchEventCalibrate : public ui::PlatformEventObserver {
     if (event->root_location() == event->location()) {
       // Usually those will be equal,
       // if not, I am not sure what the correct value should be.
-      event->set_root_location(gfx::Point(x, y));
+      event->set_root_location(gfx::PointF(x, y));
     }
-    event->set_location(gfx::Point(x, y));
+    event->set_location(gfx::PointF(x, y));
   }
 
  private: