Allow embedders to provide a custom view for popup (select box) widgets,

content/browser/web_contents/web_contents_view_gtk.cc

Index: content/browser/web_contents/web_contents_view_gtk.cc
===================================================================
--- content/browser/web_contents/web_contents_view_gtk.cc	(revision 175506)
+++ content/browser/web_contents/web_contents_view_gtk.cc	(working copy)
@@ -149,6 +149,11 @@
   return view;
 }
 
+RenderWidgetHostView* WebContentsViewGtk::CreateViewForPopupWidget(
+    RenderWidgetHost* render_widget_host) {
+  return RenderWidgetHostViewPort::CreateViewForWidget(render_widget_host);
+}
+
 gfx::NativeView WebContentsViewGtk::GetNativeView() const {
   if (delegate_.get())
     return delegate_->GetNativeView();