diff -r 000000000000 -r 6474c204b198 ipc/glue/nsIIPCBackgroundChildCreateCallback.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/glue/nsIIPCBackgroundChildCreateCallback.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,70 @@
+/* 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 mozilla_ipc_nsiipcbackgroundchildcreatecallback_h
+#define mozilla_ipc_nsiipcbackgroundchildcreatecallback_h
+
+#include "mozilla/Attributes.h"
+#include "nsISupports.h"
+
+namespace mozilla {
+namespace ipc {
+
+class PBackgroundChild;
+
+} // namespace ipc
+} // namespace mozilla
+
+#define NS_IIPCBACKGROUNDCHILDCREATECALLBACK_IID                               \
+  {0x4de01707, 0x70e3, 0x4181, {0xbc, 0x9f, 0xa3, 0xec, 0xfe, 0x74, 0x1a, 0xe3}}
+
+class NS_NO_VTABLE nsIIPCBackgroundChildCreateCallback : public nsISupports
+{
+public:
+  typedef mozilla::ipc::PBackgroundChild PBackgroundChild;
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IIPCBACKGROUNDCHILDCREATECALLBACK_IID)
+
+  // This will be called upon successful creation of a PBackgroundChild actor.
+  // The actor is unique per-thread and must not be shared across threads. It
+  // may be saved and reused on the same thread for as long as the thread lives.
+  // After this callback BackgroundChild::GetForCurrentThread() will return the
+  // same actor.
+  virtual void
+  ActorCreated(PBackgroundChild*) = 0;
+
+  // This will be called if for some reason the PBackgroundChild actor cannot be
+  // created. This should never be called in child processes as the failure to
+  // create the actor should result in the termination of the child process
+  // first. This may be called for cross-thread actors in the main process.
+  virtual void
+  ActorFailed() = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIIPCBackgroundChildCreateCallback,
+                              NS_IIPCBACKGROUNDCHILDCREATECALLBACK_IID)
+
+#define NS_DECL_NSIIPCBACKGROUNDCHILDCREATECALLBACK                            \
+  virtual void                                                                 \
+  ActorCreated(mozilla::ipc::PBackgroundChild*) MOZ_OVERRIDE;                  \
+  virtual void                                                                 \
+  ActorFailed() MOZ_OVERRIDE;
+
+#define NS_FORWARD_NSIIPCBACKGROUNDCHILDCREATECALLBACK(_to)                    \
+  virtual void                                                                 \
+  ActorCreated(mozilla::ipc::PBackgroundChild* aActor) MOZ_OVERRIDE            \
+  { _to ActorCreated(aActor); }                                                \
+  virtual void                                                                 \
+  ActorFailed() MOZ_OVERRIDE                                                   \
+  { _to ActorFailed(); }
+
+#define NS_FORWARD_SAFE_NSIIPCBACKGROUNDCHILDCREATECALLBACK(_to)               \
+  virtual void                                                                 \
+  ActorCreated(mozilla::ipc::PBackgroundChild* aActor) MOZ_OVERRIDE            \
+  { if (_to) { _to->ActorCreated(aActor); } }                                  \
+  virtual void                                                                 \
+  ActorFailed() MOZ_OVERRIDE                                                   \
+  { if (_to) { _to->ActorFailed(); } }
+
+#endif // mozilla_ipc_nsiipcbackgroundchildcreatecallback_h