Have FrameFetchContext check for frame detached status more often.

Source/core/loader/FrameFetchContext.h

Index: Source/core/loader/FrameFetchContext.h
diff --git a/Source/core/loader/FrameFetchContext.h b/Source/core/loader/FrameFetchContext.h
index c2f63908575aa4b6389a8783a7ad483c8830e421..dd850e2dcf820fbd0f7d03bbe3a0d8b7c25cfa5f 100644
--- a/Source/core/loader/FrameFetchContext.h
+++ b/Source/core/loader/FrameFetchContext.h
@@ -58,7 +58,7 @@ public:
 
     LocalFrame* frame() const override; // Can be null
     Document* document() const override { return m_document; } // Can be null
-    void setDocument(RawPtr<Document> document) { m_document = document; }
+    void setDocument(Document* document) { m_document = document; }
     DocumentLoader* documentLoader() const override { return m_documentLoader; }
     void clearDocumentLoader() { m_documentLoader = nullptr; }