diff -r 000000000000 -r 6474c204b198 dom/plugins/ipc/PluginBackgroundDestroyer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/plugins/ipc/PluginBackgroundDestroyer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: sw=4 ts=8 et :
+ */
+/* 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 dom_plugins_PluginBackgroundDestroyer
+#define dom_plugins_PluginBackgroundDestroyer
+
+#include "mozilla/plugins/PPluginBackgroundDestroyerChild.h"
+#include "mozilla/plugins/PPluginBackgroundDestroyerParent.h"
+
+#include "gfxSharedImageSurface.h"
+
+class gfxASurface;
+
+namespace mozilla {
+namespace plugins {
+
+/**
+ * When instances of this class are destroyed, the old background goes
+ * along with them, completing the destruction process (whether or not
+ * the plugin stayed alive long enough to ack).
+ */
+class PluginBackgroundDestroyerParent : public PPluginBackgroundDestroyerParent {
+public:
+    PluginBackgroundDestroyerParent(gfxASurface* aDyingBackground);
+
+    virtual ~PluginBackgroundDestroyerParent();
+
+private:
+    virtual void ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE;
+
+    nsRefPtr<gfxASurface> mDyingBackground;
+};
+
+/**
+ * This class exists solely to instruct its instance to release its
+ * current background, a new one may be coming.
+ */
+class PluginBackgroundDestroyerChild : public PPluginBackgroundDestroyerChild {
+public:
+    PluginBackgroundDestroyerChild() { }
+    virtual ~PluginBackgroundDestroyerChild() { }
+
+private:
+    // Implementing this for good hygiene.
+    virtual void ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE
+    { }
+};
+
+} // namespace plugins
+} // namespace mozilla
+
+#endif  // dom_plugins_PluginBackgroundDestroyer