At least for the Gdk where Settings::setUsesPageCache is not called the above named variable might be uninitialized. I have decided to make false the default value as the current non Mac ports (Qt,Gdk,Wx) do not have a PageCache implementation and the Mac port is calling Settings::setUsesPageCache through the WebView.mm wrapper
Created attachment 15322 [details] Initialize Settings::m_usesPageCache
Comment on attachment 15322 [details] Initialize Settings::m_usesPageCache r=me
Landed in r23910.