gfx: Make conversions from Size to SizeF be explicit.

content/renderer/child_frame_compositing_helper.cc

Index: content/renderer/child_frame_compositing_helper.cc
diff --git a/content/renderer/child_frame_compositing_helper.cc b/content/renderer/child_frame_compositing_helper.cc
index adec05be8e643a2a0f4ccb28ddc124bda9d6ac26..4f23d6cfeb9dfacd7ec2e5ffbeabd19facf71bb7 100644
--- a/content/renderer/child_frame_compositing_helper.cc
+++ b/content/renderer/child_frame_compositing_helper.cc
@@ -161,8 +161,8 @@ void ChildFrameCompositingHelper::CheckSizeAndAdjustLayerProperties(
     // The container size is in DIP, so is the layer size.
     // Buffer size is in physical pixels, so we need to adjust
     // it by the device scale factor.
-    gfx::Size device_scale_adjusted_size = gfx::ToFlooredSize(
-        gfx::ScaleSize(buffer_size_, 1.0f / device_scale_factor));
+    gfx::Size device_scale_adjusted_size =
+        gfx::ScaleToFlooredSize(buffer_size_, 1.0f / device_scale_factor);
     layer->SetBounds(device_scale_adjusted_size);
   }