Mutual exclusion between gconf and the glib main loop.

net/proxy/proxy_config_service_linux.cc

Index: net/proxy/proxy_config_service_linux.cc
===================================================================
--- net/proxy/proxy_config_service_linux.cc	(revision 14449)
+++ net/proxy/proxy_config_service_linux.cc	(working copy)
@@ -8,7 +8,9 @@
 #include <gdk/gdk.h>
 #include <stdlib.h>
 
+#include "base/lock.h"
 #include "base/logging.h"
+#include "base/message_pump_glib.h"
 #include "base/string_tokenizer.h"
 #include "base/string_util.h"
 #include "googleurl/src/url_canon.h"
@@ -258,10 +260,17 @@
   }
 
   virtual void Enter() {
-    gdk_threads_enter();
+    // Gconf is not thread-safe against itself, and it's meant to be
+    // used from the thread running the glib main loop. The proxy
+    // configuration is being fetched from the I/O thread, while the
+    // glib main loop runs in the UI thread. gconf has callbacks,
+    // timeouts and idles that will be dispatched from the glib main
+    // loop. We take this lock to enforce mutual exclusion with the
+    // glib main loop.
+    base::MessagePumpForUI::glib_main_loop_lock_.Acquire();
   }
   virtual void Leave() {
-    gdk_threads_leave();
+    base::MessagePumpForUI::glib_main_loop_lock_.Release();
   }
 
   virtual bool InitIfNeeded() {