This happens because we are not forwarding the settings to the child webView.
Created attachment 45592 [details]
Make sure settings are forwarded to child WebViews.
Attachment 45592 [details] did not pass style-queue:
Failed to run "WebKitTools/Scripts/check-webkit-style" exit_code: 1
WebKitTools/DumpRenderTree/gtk/DumpRenderTree.cpp:787: Extra space before ( in function call [whitespace/parens] 
Total errors found: 1
Landed as r52614, reviewed on IRC by Holger.