--- a/xpcom/base/nsRefPtr.h
+++ b/xpcom/base/nsRefPtr.h
@@ -2,17 +2,19 @@
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* 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 nsRefPtr_h
 #define nsRefPtr_h
 
-#include "nsCOMPtr.h"
+#include "AlreadyAddRefed.h"
+#include "nsDebug.h"
+#include "nsISupportsUtils.h"
 
 /*****************************************************************************/
 
 // template <class T> class nsRefPtrGetterAddRefs;
 
 class nsCOMPtr_helper;
 
 template <class T>
@@ -264,22 +266,18 @@ public:
     NS_PRECONDITION(mRawPtr != 0,
                     "You can't dereference a NULL nsRefPtr with operator*().");
     return *get();
   }
 
   T**
   StartAssignment()
   {
-#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
-    return reinterpret_cast<T**>(begin_assignment());
-#else
     assign_assuming_AddRef(0);
     return reinterpret_cast<T**>(&mRawPtr);
-#endif
   }
 };
 
 template <class T>
 nsRefPtr<T>::nsRefPtr(const nsCOMPtr_helper& aHelper)
 {
   void* newRawPtr;
   if (NS_FAILED(aHelper(NS_GET_TEMPLATE_IID(T), &newRawPtr))) {
@@ -468,47 +466,49 @@ operator!=(const nsRefPtr<T>& aLhs, U* a
 
 template <class T, class U>
 inline bool
 operator!=(U* aLhs, const nsRefPtr<T>& aRhs)
 {
   return const_cast<const U*>(aLhs) != static_cast<const T*>(aRhs.get());
 }
 
-
+namespace detail {
+class nsRefPtrZero;
+}
 
 // Comparing an |nsRefPtr| to |0|
 
 template <class T>
 inline bool
-operator==(const nsRefPtr<T>& aLhs, NSCAP_Zero* aRhs)
+operator==(const nsRefPtr<T>& aLhs, ::detail::nsRefPtrZero* aRhs)
 // specifically to allow |smartPtr == 0|
 {
   return static_cast<const void*>(aLhs.get()) == reinterpret_cast<const void*>(aRhs);
 }
 
 template <class T>
 inline bool
-operator==(NSCAP_Zero* aLhs, const nsRefPtr<T>& aRhs)
+operator==(::detail::nsRefPtrZero* aLhs, const nsRefPtr<T>& aRhs)
 // specifically to allow |0 == smartPtr|
 {
   return reinterpret_cast<const void*>(aLhs) == static_cast<const void*>(aRhs.get());
 }
 
 template <class T>
 inline bool
-operator!=(const nsRefPtr<T>& aLhs, NSCAP_Zero* aRhs)
+operator!=(const nsRefPtr<T>& aLhs, ::detail::nsRefPtrZero* aRhs)
 // specifically to allow |smartPtr != 0|
 {
   return static_cast<const void*>(aLhs.get()) != reinterpret_cast<const void*>(aRhs);
 }
 
 template <class T>
 inline bool
-operator!=(NSCAP_Zero* aLhs, const nsRefPtr<T>& aRhs)
+operator!=(::detail::nsRefPtrZero* aLhs, const nsRefPtr<T>& aRhs)
 // specifically to allow |0 != smartPtr|
 {
   return reinterpret_cast<const void*>(aLhs) != static_cast<const void*>(aRhs.get());
 }
 
 
 template <class SourceType, class DestinationType>
 inline nsresult