import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

widget/WidgetTraceEvent.h

@@ -0,0 +1,27 @@
+/* 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/. */
+
+#ifndef WIDGET_PUBLIC_WIDGETTRACEEVENT_H_
+#define WIDGET_PUBLIC_WIDGETTRACEEVENT_H_
+
+namespace mozilla {
+
+// Perform any required initialization in the widget backend for
+// event tracing. Return true if initialization was successful.
+bool InitWidgetTracing();
+
+// Perform any required cleanup in the widget backend for event tracing.
+void CleanUpWidgetTracing();
+
+// Fire a tracer event at the UI-thread event loop, and block until
+// the event is processed. This should only be called by
+// a thread that's not the UI thread.
+bool FireAndWaitForTracerEvent();
+
+// Signal that the event has been received by the event loop.
+void SignalTracerThread();
+
+} // namespace mozilla
+
+#endif  // WIDGET_PUBLIC_WIDGETTRACEEVENT_H_