Move CreateFakeXEvent to x11_util.{h,cc}.

ui/base/keycodes/keyboard_code_conversion_x.h

Index: ui/base/keycodes/keyboard_code_conversion_x.h
diff --git a/ui/base/keycodes/keyboard_code_conversion_x.h b/ui/base/keycodes/keyboard_code_conversion_x.h
index 77794835c5b9d0e4c608993dbf188bb5d45708da..19a1fe2a6ba103010a97b28511c5379b0565b1d7 100644
--- a/ui/base/keycodes/keyboard_code_conversion_x.h
+++ b/ui/base/keycodes/keyboard_code_conversion_x.h
@@ -5,6 +5,7 @@
 #ifndef UI_BASE_KEYCODES_KEYBOARD_CODE_CONVERSION_X_H_
 #define UI_BASE_KEYCODES_KEYBOARD_CODE_CONVERSION_X_H_
 
+#include "ui/base/events.h"
 #include "ui/base/keycodes/keyboard_codes_posix.h"
 #include "ui/base/ui_export.h"
 
@@ -25,6 +26,11 @@ UI_EXPORT int XKeysymForWindowsKeyCode(KeyboardCode keycode, bool shift);
 // Converts an X keycode into an X KeySym.
 unsigned int DefaultXKeysymFromHardwareKeycode(unsigned int keycode);
 
+// Creates a fake XEvent for testing. The caller must delete the returned value.
+XEvent* CreateXEventForTesting(EventType type,
+                               KeyboardCode key_code,
+                               int flags);
+
 }  // namespace ui
 
 #endif  // UI_BASE_KEYCODES_KEYBOARD_CODE_CONVERSION_X_H_