Make utility process run in-process when running in single-process mode.

content/browser/plugin_service_impl.cc

Index: content/browser/plugin_service_impl.cc
===================================================================
--- content/browser/plugin_service_impl.cc	(revision 210446)
+++ content/browser/plugin_service_impl.cc	(working copy)
@@ -66,6 +66,13 @@
 #else
   // If on POSIX, we don't want to load the list of NPAPI plugins in-process as
   // that causes instability.
+
+  // Can't load the plugins on the utility thread when in single process mode
+  // since that requires using WebKit and GTK and they can only be used on the
+  // main thread.
+  if (RenderProcessHost::run_renderer_in_process())
+    return true;
+
   return !webkit::npapi::NPAPIPluginsSupported();
 #endif
 }