diff -r 000000000000 -r 6474c204b198 xpcom/base/nsISupportsBase.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/base/nsISupportsBase.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/* 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/. */
+// IWYU pragma: private, include "nsISupports.h"
+
+#ifndef nsISupportsBase_h__
+#define nsISupportsBase_h__
+
+#ifndef nscore_h___
+#include "nscore.h"
+#endif
+
+#ifndef nsID_h__
+#include "nsID.h"
+#endif
+
+
+/*@{*/
+/**
+ * IID for the nsISupports interface
+ * {00000000-0000-0000-c000-000000000046}
+ *
+ * To maintain binary compatibility with COM's IUnknown, we define the IID
+ * of nsISupports to be the same as that of COM's IUnknown.
+ */
+#define NS_ISUPPORTS_IID                                                      \
+  { 0x00000000, 0x0000, 0x0000,                                               \
+    {0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46} }
+
+/**
+ * Basic component object model interface. Objects which implement
+ * this interface support runtime interface discovery (QueryInterface)
+ * and a reference counted memory model (AddRef/Release). This is
+ * modelled after the win32 IUnknown API.
+ */
+class NS_NO_VTABLE nsISupports {
+public:
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ISUPPORTS_IID)
+
+  /**
+   * @name Methods
+   */
+
+  //@{
+  /**
+   * A run time mechanism for interface discovery.
+   * @param aIID [in] A requested interface IID
+   * @param aInstancePtr [out] A pointer to an interface pointer to
+   * receive the result.
+   * @return <b>NS_OK</b> if the interface is supported by the associated
+   * instance, <b>NS_NOINTERFACE</b> if it is not.
+   *
+   * aInstancePtr must not be null.
+   */
+  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) = 0;
+  /**
+   * Increases the reference count for this interface.
+   * The associated instance will not be deleted unless
+   * the reference count is returned to zero.
+   *
+   * @return The resulting reference count.
+   */
+  NS_IMETHOD_(MozExternalRefCountType) AddRef(void) = 0;
+
+  /**
+   * Decreases the reference count for this interface.
+   * Generally, if the reference count returns to zero,
+   * the associated instance is deleted.
+   *
+   * @return The resulting reference count.
+   */
+  NS_IMETHOD_(MozExternalRefCountType) Release(void) = 0;
+
+  //@}
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsISupports, NS_ISUPPORTS_IID)
+
+/*@}*/
+
+#endif