Refactor the API for setting dynamic resource load priorities

Source/core/fetch/ResourceLoaderSet.h

Index: Source/core/fetch/ResourceLoaderSet.h
diff --git a/Source/core/fetch/ResourceLoaderSet.h b/Source/core/fetch/ResourceLoaderSet.h
index a344bf789b9ddf97be50b41a432d460c4dec28f2..69c550444aaddd2d43c9e80d18fafec4cddb868a 100644
--- a/Source/core/fetch/ResourceLoaderSet.h
+++ b/Source/core/fetch/ResourceLoaderSet.h
@@ -50,6 +50,7 @@ public:
     void cancelAll();
     void setAllDefersLoading(bool);
     int size() const { return m_set.size(); }
+    const HeapHashSet<Member<ResourceLoader>>& hashSet() const { return m_set; }
 
 private:
     SetType m_set;