gfx: Make conversions from Size to SizeF be explicit.

ui/aura/test/test_screen.cc

Index: ui/aura/test/test_screen.cc
diff --git a/ui/aura/test/test_screen.cc b/ui/aura/test/test_screen.cc
index cdeb093eda082e57cb35f87b2e1679741bbd3709..1320b1c6f182d852550cfb88002857d552779b0a 100644
--- a/ui/aura/test/test_screen.cc
+++ b/ui/aura/test/test_screen.cc
@@ -116,8 +116,8 @@ gfx::Transform TestScreen::GetUIScaleTransform() const {
 void TestScreen::OnWindowBoundsChanged(
     Window* window, const gfx::Rect& old_bounds, const gfx::Rect& new_bounds) {
   DCHECK_EQ(host_->window(), window);
-  display_.SetSize(gfx::ToFlooredSize(
-      gfx::ScaleSize(new_bounds.size(), display_.device_scale_factor())));
+  display_.SetSize(gfx::ScaleToFlooredSize(new_bounds.size(),
+                                           display_.device_scale_factor()));
 }
 
 void TestScreen::OnWindowDestroying(Window* window) {