Make copyToVector() robust against conservative GCs.

third_party/WebKit/Source/wtf/HashSet.h

Index: third_party/WebKit/Source/wtf/HashSet.h
diff --git a/third_party/WebKit/Source/wtf/HashSet.h b/third_party/WebKit/Source/wtf/HashSet.h
index 08e5902a777725d53cd152136134bddb77fb09ac..5aa01929646c90a571b3aa475512aabb3e8433e1 100644
--- a/third_party/WebKit/Source/wtf/HashSet.h
+++ b/third_party/WebKit/Source/wtf/HashSet.h
@@ -275,7 +275,11 @@ inline void copyToVector(const C& collection, W& vector)
 {
     typedef typename C::const_iterator iterator;
 
-    vector.resize(collection.size());
+    {
+        // Disallow GC across resize allocation, see crbug.com/568173
+        typename W::GCForbiddenScope scope;
+        vector.resize(collection.size());
+    }
 
     iterator it = collection.begin();
     iterator end = collection.end();