Use the screen info's scale factor to scale the drag image

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 00c278e9debd13901b9162cceacf0ac203057a2b..619327b7355a74580b64b820c1122ddceb7df97d 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -2251,6 +2251,10 @@ gfx::Size RenderViewImpl::GetSize() const {
   return size();
 }
 
+float RenderViewImpl::GetDeviceScaleFactor() const {
+  return device_scale_factor_;
+}
+
 WebPreferences& RenderViewImpl::GetWebkitPreferences() {
   return webkit_preferences_;
 }