Revert "Refactor MessagePumpX to dispatch events inside of the source Dispatch function."

base/message_pump_gtk.cc

Index: base/message_pump_gtk.cc
diff --git a/base/message_pump_gtk.cc b/base/message_pump_gtk.cc
index 2c526ca512016d635d063e1092bbc59e86936f59..4f4f9816926aba321b59f22ad1f07929a5bca494 100644
--- a/base/message_pump_gtk.cc
+++ b/base/message_pump_gtk.cc
@@ -91,6 +91,11 @@ Display* MessagePumpGtk::GetDefaultXDisplay() {
   return display ? GDK_DISPLAY_XDISPLAY(display) : NULL;
 }
 
+bool MessagePumpGtk::RunOnce(GMainContext* context, bool block) {
+  // g_main_context_iteration returns true if events have been dispatched.
+  return g_main_context_iteration(context, block);
+}
+
 void MessagePumpGtk::WillProcessEvent(GdkEvent* event) {
   FOR_EACH_OBSERVER(MessagePumpObserver, observers(), WillProcessEvent(event));
 }