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

Source/platform/network/ResourceRequest.cpp

Index: Source/platform/network/ResourceRequest.cpp
diff --git a/Source/platform/network/ResourceRequest.cpp b/Source/platform/network/ResourceRequest.cpp
index 0aa61148ef41fccc15fd1065498432202bb794ee..9b54df08603c5a0cff8e34852108e1d3cc93a97b 100644
--- a/Source/platform/network/ResourceRequest.cpp
+++ b/Source/platform/network/ResourceRequest.cpp
@@ -240,7 +240,7 @@ void ResourceRequest::addHTTPHeaderField(const AtomicString& name, const AtomicS
 {
     HTTPHeaderMap::AddResult result = m_httpHeaderFields.add(name, value);
     if (!result.isNewEntry)
-        result.iterator->value = result.iterator->value + ',' + value;
+        result.storedValue->value = result.storedValue->value + ',' + value;
 }
 
 void ResourceRequest::addHTTPHeaderFields(const HTTPHeaderMap& headerFields)