diff --git a/mozilla/xpcom/ds/nsArray.cpp b/mozilla/xpcom/ds/nsArray.cpp
index 3e512a3a596..0a099645537 100644
--- a/mozilla/xpcom/ds/nsArray.cpp
+++ b/mozilla/xpcom/ds/nsArray.cpp
@@ -47,7 +47,7 @@ struct findIndexOfClosure
     PRUint32 resultIndex;
 };
 
-static PRBool FindElementCallback(nsISupports* aElement, void* aClosure);
+static PRBool FindElementCallback(void* aElement, void* aClosure);
 
 
 NS_IMPL_ISUPPORTS2(nsArray, nsIArray, nsIMutableArray)
@@ -133,14 +133,17 @@ nsArray::Clear()
 }
 
 PRBool
-FindElementCallback(nsISupports *aElement, void* aClosure)
+FindElementCallback(void *aElement, void* aClosure)
 {
     findIndexOfClosure* closure =
         NS_STATIC_CAST(findIndexOfClosure*, aClosure);
 
+    nsISupports* element =
+        NS_STATIC_CAST(nsISupports*, aElement);
+    
     // don't start searching until we're past the startIndex
     if (closure->resultIndex >= closure->startIndex &&
-        aElement == closure->targetElement) {
+        element == closure->targetElement) {
         return PR_FALSE;    // stop! We found it
     }
     closure->resultIndex++;
diff --git a/mozilla/xpcom/ds/nsArray.h b/mozilla/xpcom/ds/nsArray.h
index 12e070a89d4..316bf300d2f 100644
--- a/mozilla/xpcom/ds/nsArray.h
+++ b/mozilla/xpcom/ds/nsArray.h
@@ -81,7 +81,7 @@ public:
     NS_DECL_NSIMUTABLEARRAY
 
 private:
-    nsCOMArray<nsISupports> mArray;
+    nsCOMArray_base mArray;
 };
 
 
diff --git a/mozilla/xpcom/ds/nsCOMArray.h b/mozilla/xpcom/ds/nsCOMArray.h
index 95c2cc84400..3b63b41c827 100644
--- a/mozilla/xpcom/ds/nsCOMArray.h
+++ b/mozilla/xpcom/ds/nsCOMArray.h
@@ -48,6 +48,7 @@
 // work of this class in the XPCOM dll
 class NS_COM nsCOMArray_base
 {
+    friend class nsArray;
 protected:
     nsCOMArray_base() {}
     nsCOMArray_base(PRInt32 aCount) : mArray(aCount) {}
@@ -61,6 +62,10 @@ protected:
         return mArray.EnumerateForwards(aFunc, aData);
     }
     
+    PRBool EnumerateBackwards(nsVoidArrayEnumFunc aFunc, void* aData) {
+        return mArray.EnumerateBackwards(aFunc, aData);
+    }
+    
     // any method which is not a direct forward to mArray should
     // avoid inline bodies, so that the compiler doesn't inline them
     // all over the place
@@ -120,7 +125,9 @@ class nsCOMArray : public nsCOMArray_base
     nsCOMArray() {}
     nsCOMArray(PRInt32 aCount) : nsCOMArray_base(aCount) {}
     
-    nsCOMArray(const nsCOMArray_base& aOther) : nsCOMArray_base(aOther) { }
+    // only to be used by trusted classes who are going to pass us the
+    // right type!
+    nsCOMArray(const nsCOMArray<T>& aOther) : nsCOMArray_base(aOther) { }
 
     ~nsCOMArray() {}
 
@@ -176,6 +183,11 @@ class nsCOMArray : public nsCOMArray_base
                                                   aData);
     }
 
+    PRBool EnumerateBackwards(nsCOMArrayEnumFunc aFunc, void* aData) {
+        return nsCOMArray_base::EnumerateBackwards(nsVoidArrayEnumFunc(aFunc),
+                                                  aData);
+    }
+
     // append an object, growing the array as necessary
     PRBool AppendObject(T *aObject) {
         return nsCOMArray_base::AppendObject(aObject);
@@ -194,10 +206,9 @@ class nsCOMArray : public nsCOMArray_base
         return nsCOMArray_base::RemoveObjectAt(aIndex);
     }
 
- private:
+private:
 
     // don't implement these!
-    nsCOMArray(const nsCOMArray& other);
     nsCOMArray& operator=(const nsCOMArray& other);
 };