Run event executor on the ui thread to remove the need to explicitly XFlush() the XTest calls.

base/message_loop.cc

Index: base/message_loop.cc
diff --git a/base/message_loop.cc b/base/message_loop.cc
index d83adccec08b56f8cdeb991c1b06af60d7a877e0..453172bb26776bc371cf675e8fb34e7e835a1e6b 100644
--- a/base/message_loop.cc
+++ b/base/message_loop.cc
@@ -4,6 +4,11 @@
 
 #include "base/message_loop.h"
 
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+#include <gdk/gdk.h>
+#include <gdk/gdkx.h>
+#endif
+
 #include <algorithm>
 
 #include "base/compiler_specific.h"
@@ -664,6 +669,13 @@ void MessageLoopForUI::DidProcessMessage(const MSG& message) {
 }
 #endif  // defined(OS_WIN)
 
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+Display* MessageLoopForUI::get_display()
+{
+  return gdk_x11_get_default_xdisplay();
+}
+#endif
+
 #if !defined(OS_MACOSX) && !defined(OS_NACL)
 void MessageLoopForUI::AddObserver(Observer* observer) {
   pump_ui()->AddObserver(observer);