Bug 1341678 P1 Make Request::Constructor() expect over-writing a copied body with an initializer. r=asuth

dom/fetch/Request.cpp

@@ -277,7 +277,7 @@ Request::Constructor(const GlobalObject& aGlobal,
                      const RequestOrUSVString& aInput,
                      const RequestInit& aInit, ErrorResult& aRv)
 {
-  nsCOMPtr<nsIInputStream> temporaryBody;
+  bool hasCopiedBody = false;
   RefPtr<InternalRequest> request;
 
   nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
@@ -290,8 +290,10 @@ Request::Constructor(const GlobalObject& aGlobal,
       aRv.ThrowTypeError<MSG_FETCH_BODY_CONSUMED_ERROR>();
       return nullptr;
     }
+
+    // The body will be copied when GetRequestConstructorCopy() is executed.
     if (body) {
-      temporaryBody = body;
+      hasCopiedBody = true;
     }
 
     request = inputReq->GetInternalRequest();
@@ -535,7 +537,7 @@ Request::Constructor(const GlobalObject& aGlobal,
   }
 
   if ((aInit.mBody.WasPassed() && !aInit.mBody.Value().IsNull()) ||
-      temporaryBody) {
+      hasCopiedBody) {
     // HEAD and GET are not allowed to have a body.
     nsAutoCString method;
     request->GetMethod(method);
@@ -561,7 +563,7 @@ Request::Constructor(const GlobalObject& aGlobal,
         return nullptr;
       }
 
-      temporaryBody = stream;
+      nsCOMPtr<nsIInputStream> temporaryBody = stream;
 
       if (!contentTypeWithCharset.IsVoid() &&
           !requestHeaders->Has(NS_LITERAL_CSTRING("Content-Type"), aRv)) {
@@ -574,6 +576,11 @@ Request::Constructor(const GlobalObject& aGlobal,
       }
 
       request->ClearCreatedByFetchEvent();
+
+      if (hasCopiedBody) {
+        request->SetBody(nullptr);
+      }
+
       request->SetBody(temporaryBody);
     }
   }