Bug 1629395 - Overwrite integrity attribute in fetch() is allowed, r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D70798

--HG--
extra : moz-landing-system : lando

dom/fetch/InternalRequest.h

@@ -240,8 +240,8 @@ class InternalRequest final {
   }
 
   const nsString& GetIntegrity() const { return mIntegrity; }
+
   void SetIntegrity(const nsAString& aIntegrity) {
-    MOZ_ASSERT(mIntegrity.IsEmpty());
     mIntegrity.Assign(aIntegrity);
   }