Simpler return value from HashTable::add()/HashMap::add() and others

Source/wtf/RefPtrHashMap.h

Index: Source/wtf/RefPtrHashMap.h
diff --git a/Source/wtf/RefPtrHashMap.h b/Source/wtf/RefPtrHashMap.h
index 2fa418420ae79ad84a6484461bd65cd45fe4f50b..009bbc4f5f38ca43e5c3fbc20025a8c46b6142eb 100644
--- a/Source/wtf/RefPtrHashMap.h
+++ b/Source/wtf/RefPtrHashMap.h
@@ -217,7 +217,7 @@ namespace WTF {
         AddResult result = inlineAdd(key, mapped);
         if (!result.isNewEntry) {
             // The inlineAdd call above found an existing hash table entry; we need to set the mapped value.
-            MappedTraits::store(mapped, result.iterator->value);
+            MappedTraits::store(mapped, result.storedValue->value);
         }
         return result;
     }
@@ -229,7 +229,7 @@ namespace WTF {
         AddResult result = inlineAdd(key, mapped);
         if (!result.isNewEntry) {
             // The inlineAdd call above found an existing hash table entry; we need to set the mapped value.
-            MappedTraits::store(mapped, result.iterator->value);
+            MappedTraits::store(mapped, result.storedValue->value);
         }
         return result;
     }