Bug 272381 Crash when printing a iframe [PoC included][@ GlobalWindowImpl::Print] GlobalWindowImpl::GetInterface is broken

r=peterv sr=peterv

dom/src/base/nsGlobalWindow.cpp

@@ -4548,7 +4548,7 @@ GlobalWindowImpl::GetInterface(const nsIID & aIID, void **aSink)
     return QueryInterface(aIID, aSink);
   }
 
-  return NS_OK;
+  return *aSink ? NS_ERROR_NO_INTERFACE : NS_OK;
 }
 
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