diff -r 000000000000 -r 6474c204b198 widget/cocoa/CustomCocoaEvents.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/cocoa/CustomCocoaEvents.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file defines constants to be used in the "subtype" field of
+ * NSApplicationDefined type NSEvents.
+ */
+
+#ifndef WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_
+#define WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_
+
+// Empty event, just used for prodding the event loop into responding.
+const short kEventSubtypeNone = 0;
+// Tracer event, used for timing the event loop responsiveness.
+const short kEventSubtypeTrace = 1;
+
+#endif /* WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_ */