import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/media/gmp/GMPCallbackBase.h

@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 GMPCallbackBase_h_
+#define GMPCallbackBase_h_
+
+class GMPCallbackBase
+{
+public:
+  virtual ~GMPCallbackBase() {}
+
+  // The GMP code will call this if the codec crashes or shuts down.  It's
+  // expected that the consumer (destination of this callback) will respond
+  // by dropping their reference to the proxy, allowing the proxy/parent to
+  // be destroyed.
+  virtual void Terminated() = 0;
+};
+
+#endif