Add a flag for enabling the threaded parser

webkit/glue/webpreferences.cc

Index: webkit/glue/webpreferences.cc
===================================================================
--- webkit/glue/webpreferences.cc	(revision 182155)
+++ webkit/glue/webpreferences.cc	(working copy)
@@ -88,6 +88,7 @@
       accelerated_compositing_for_scrollable_frames_enabled(false),
       composited_scrolling_for_frames_enabled(false),
       mock_scrollbars_enabled(false),
+      threaded_html_parser(false),
       show_paint_rects(false),
       render_vsync_enabled(true),
       asynchronous_spell_checking_enabled(true),
@@ -377,6 +378,8 @@
   // Uses the mock theme engine for scrollbars.
   settings->setMockScrollbarsEnabled(mock_scrollbars_enabled);
 
+  settings->setThreadedHTMLParser(threaded_html_parser);
+
   // Display the current compositor tree as overlay if requested on
   // the command line
   settings->setShowPlatformLayerTree(show_composited_layer_tree);