Add a RefPtr<Frame> for child in FrameLoader::checkLoadCompleteForThisFrame

Source/core/loader/FrameLoader.cpp

Index: Source/core/loader/FrameLoader.cpp
diff --git a/Source/core/loader/FrameLoader.cpp b/Source/core/loader/FrameLoader.cpp
index 8147af34e14c1077d603442f6fea78bacb2dd1b5..155c93fe947416aa6b03d7fdf6d826df77cbe693 100644
--- a/Source/core/loader/FrameLoader.cpp
+++ b/Source/core/loader/FrameLoader.cpp
@@ -948,9 +948,9 @@ bool FrameLoader::checkLoadCompleteForThisFrame()
     RefPtr<LocalFrame> protect(m_frame);
 
     bool allChildrenAreDoneLoading = true;
-    for (Frame* child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
+    for (RefPtr<Frame> child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
         if (child->isLocalFrame())
-            allChildrenAreDoneLoading &= toLocalFrame(child)->loader().checkLoadCompleteForThisFrame();
+            allChildrenAreDoneLoading &= toLocalFrame(child.get())->loader().checkLoadCompleteForThisFrame();
     }
 
     if (m_state == FrameStateProvisional && m_provisionalDocumentLoader) {