CREDENTIAL: Extend FormData opacity to created Request objects

Source/modules/fetch/Body.h

Index: Source/modules/fetch/Body.h
diff --git a/Source/modules/fetch/Body.h b/Source/modules/fetch/Body.h
index 1e9ee5374eb14ee5d5a8cdba5b51b8c763dc7da7..e297d4f85e55c3cfe7bdb65cc4f4a461eecadda1 100644
--- a/Source/modules/fetch/Body.h
+++ b/Source/modules/fetch/Body.h
@@ -50,10 +50,14 @@ public:
         ActiveDOMObject::trace(visitor);
     }
 
+    void makeOpaque() { m_opaque = true; }
+    bool opaque() const { return m_opaque; }
+
 private:
     virtual String mimeType() const = 0;
 
     bool m_bodyPassed;
+    bool m_opaque;
 };
 
 } // namespace blink