Scale the scroll offset from viewport to dip in use-zoom-for-dsf mode.

content/renderer/pepper/pepper_plugin_instance_impl.cc

Index: content/renderer/pepper/pepper_plugin_instance_impl.cc
diff --git a/content/renderer/pepper/pepper_plugin_instance_impl.cc b/content/renderer/pepper/pepper_plugin_instance_impl.cc
index 921f42b4a1828e143ed950ae000c2a9411f76457..e239e22efa56ae5ccd1552af512e177e53d856fa 100644
--- a/content/renderer/pepper/pepper_plugin_instance_impl.cc
+++ b/content/renderer/pepper/pepper_plugin_instance_impl.cc
@@ -1285,8 +1285,9 @@ void PepperPluginInstanceImpl::ViewChanged(
   view_data_.css_scale *= viewport_to_dip_scale_;
   view_data_.device_scale /= viewport_to_dip_scale_;
 
-  gfx::Size scroll_offset =
-      container_->document().frame()->scrollOffset();
+  gfx::Size scroll_offset = gfx::ScaleToRoundedSize(
+      container_->document().frame()->scrollOffset(), viewport_to_dip_scale_);
+
   view_data_.scroll_offset = PP_MakePoint(scroll_offset.width(),
                                           scroll_offset.height());