Made MessagePump a non-thread safe class.

base/message_loop/message_pump_gtk.cc

Index: base/message_loop/message_pump_gtk.cc
diff --git a/base/message_loop/message_pump_gtk.cc b/base/message_loop/message_pump_gtk.cc
index 8fa8cf2d081e9113c1e49351e93d101e539715a8..ad6511318ab1173c41e357d860e7165896a12f23 100644
--- a/base/message_loop/message_pump_gtk.cc
+++ b/base/message_loop/message_pump_gtk.cc
@@ -65,6 +65,11 @@ MessagePumpGtk::MessagePumpGtk() : MessagePumpGlib() {
   gdk_event_handler_set(&EventDispatcher, this, NULL);
 }
 
+MessagePumpGtk::~MessagePumpGtk() {
+  gdk_event_handler_set(reinterpret_cast<GdkEventFunc>(gtk_main_do_event),
+                        this, NULL);
+}
+
 void MessagePumpGtk::DispatchEvents(GdkEvent* event) {
   UNSHIPPED_TRACE_EVENT1("task", "MessagePumpGtk::DispatchEvents",
                          "type", EventToTypeString(event));
@@ -92,11 +97,6 @@ Display* MessagePumpGtk::GetDefaultXDisplay() {
   return GDK_DISPLAY_XDISPLAY(display);
 }
 
-MessagePumpGtk::~MessagePumpGtk() {
-  gdk_event_handler_set(reinterpret_cast<GdkEventFunc>(gtk_main_do_event),
-                        this, NULL);
-}
-
 void MessagePumpGtk::WillProcessEvent(GdkEvent* event) {
   FOR_EACH_OBSERVER(MessagePumpObserver, observers(), WillProcessEvent(event));
 }