Disable default use of the Plug-in XPCService until we can
figure out how to deal with the 32-bit one.

* UIProcess/Plugins/mac/PluginProcessProxyMac.mm:
(WebKit::shouldUseXPC):
(WebKit::PluginProcessProxy::platformInitializeLaunchOptions):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141052 268f45cc-cd09-0410-ab3c-d52691b4dbfc