Bug 807713 - add operator[] for nsTObserverArray. r=bsmedberg

accessible/src/base/nsAccessiblePivot.cpp

@@ -59,9 +59,9 @@ NS_IMPL_CYCLE_COLLECTION_CLASS(nsAccessiblePivot)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsAccessiblePivot)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR_AMBIGUOUS(mRoot, nsIAccessible)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR_AMBIGUOUS(mPosition, nsIAccessible)
-  uint32_t i, length = tmp->mObservers.Length();                               \
+  uint32_t i, length = tmp->mObservers.Length();
   for (i = 0; i < length; ++i) {
-    cb.NoteXPCOMChild(tmp->mObservers.ElementAt(i).get());
+    cb.NoteXPCOMChild(tmp->mObservers[i]);
   }
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 

xpcom/glue/nsTObserverArray.h

@@ -117,6 +117,16 @@ class nsAutoTObserverArray : protected nsTObserverArray_base {
       return mArray.SafeElementAt(i, def);
     }
 
+    // Shorthand for ElementAt(i)
+    elem_type& operator[](index_type i) {
+      return ElementAt(i);
+    }
+
+    // Shorthand for ElementAt(i)
+    const elem_type& operator[](index_type i) const {
+      return ElementAt(i);
+    }
+
     //
     // Search methods
     //