Made MessagePump a non-thread safe class.

base/message_loop/message_pump_gtk.h

Index: base/message_loop/message_pump_gtk.h
diff --git a/base/message_loop/message_pump_gtk.h b/base/message_loop/message_pump_gtk.h
index e22e04f971eb040aa7870682a2d57038e0ac6845..947ab885afec34a61b2249c98c223da7af89eaff 100644
--- a/base/message_loop/message_pump_gtk.h
+++ b/base/message_loop/message_pump_gtk.h
@@ -43,6 +43,7 @@ class MessagePumpDispatcher {
 class BASE_EXPORT MessagePumpGtk : public MessagePumpGlib {
  public:
   MessagePumpGtk();
+  virtual ~MessagePumpGtk();
 
   // Dispatch an available GdkEvent. Essentially this allows a subclass to do
   // some task before/after calling the default handler (EventDispatcher).
@@ -51,9 +52,6 @@ class BASE_EXPORT MessagePumpGtk : public MessagePumpGlib {
   // Returns default X Display.
   static Display* GetDefaultXDisplay();
 
- protected:
-  virtual ~MessagePumpGtk();
-
  private:
   // Invoked from EventDispatcher. Notifies all observers we're about to
   // process an event.