Remove some implicit Point to PointF conversions, add helpers.

ui/gfx/win/dpi.cc

Index: ui/gfx/win/dpi.cc
diff --git a/ui/gfx/win/dpi.cc b/ui/gfx/win/dpi.cc
index 508a2c776c3d49542eada9b76cd8aca48adcc6a7..c0c44d612b80a91e736f6d9eedcd2ba2a7a33fb3 100644
--- a/ui/gfx/win/dpi.cc
+++ b/ui/gfx/win/dpi.cc
@@ -67,11 +67,11 @@ float GetDPIScale() {
 namespace win {
 
 Point ScreenToDIPPoint(const Point& pixel_point) {
-  return ToFlooredPoint(ScalePoint(pixel_point, 1.0f / GetDPIScale()));
+  return ScaleToFlooredPoint(pixel_point, 1.0f / GetDPIScale());
 }
 
 Point DIPToScreenPoint(const Point& dip_point) {
-  return ToFlooredPoint(ScalePoint(dip_point, GetDPIScale()));
+  return ScaleToFlooredPoint(dip_point, GetDPIScale());
 }
 
 Rect ScreenToDIPRect(const Rect& pixel_bounds) {