Improve DEFINE_STATIC_LOCAL()'s handling of Blink GCed objects.

third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp

Index: third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
diff --git a/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp b/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
index 8ab707ea1f5da37c6bb95c636adf21c803f31593..7e7ed61626eb3f880782381669ce73dd462a6455 100644
--- a/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
+++ b/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
@@ -164,11 +164,11 @@ const HeapVector<Member<Element>>& DocumentOrderedMap::getAllElementsById(const
 {
     ASSERT(key);
     ASSERT(scope);
-    DEFINE_STATIC_LOCAL(Persistent<HeapVector<Member<Element>>>, emptyVector, (new HeapVector<Member<Element>>()));
+    DEFINE_STATIC_LOCAL(HeapVector<Member<Element>>, emptyVector, (new HeapVector<Member<Element>>));
 
     Map::iterator it = m_map.find(key);
     if (it == m_map.end())
-        return *emptyVector;
+        return emptyVector;
 
     Member<MapEntry>& entry = it->value;
     ASSERT(entry->count);