diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/chrome/common/notification_source.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/chrome/common/notification_source.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file defines the type used to provide sources for NotificationService
+// notifications.
+
+#ifndef CHROME_COMMON_NOTIFICATION_SOURCE_H__
+#define CHROME_COMMON_NOTIFICATION_SOURCE_H__
+
+#include "base/basictypes.h"
+
+// Do not declare a NotificationSource directly--use either
+// "Source<sourceclassname>(sourceclasspointer)" or
+// NotificationService::AllSources().
+class NotificationSource {
+ public:
+  NotificationSource(const NotificationSource& other) : ptr_(other.ptr_) { }
+  ~NotificationSource() {}
+
+  // NotificationSource can be used as the index for a map; this method
+  // returns the pointer to the current source as an identifier, for use as a
+  // map index.
+  uintptr_t map_key() const { return reinterpret_cast<uintptr_t>(ptr_); }
+
+  bool operator!=(const NotificationSource& other) const {
+    return ptr_ != other.ptr_;
+  }
+  bool operator==(const NotificationSource& other) const {
+    return ptr_ == other.ptr_;
+  }
+
+ protected:
+  NotificationSource(void* ptr) : ptr_(ptr) {}
+
+  void* ptr_;
+};
+
+template <class T>
+class Source : public NotificationSource {
+ public:
+  Source(T* ptr) : NotificationSource(ptr) {}
+
+  Source(const NotificationSource& other)
+    : NotificationSource(other) {}
+
+  T* operator->() const { return ptr(); }
+  T* ptr() const { return static_cast<T*>(ptr_); }
+};
+
+#endif  // CHROME_COMMON_NOTIFICATION_SOURCE_H__