[Fetch] Body consume function should not set bodyUsed flag.

Source/modules/serviceworkers/RespondWithObserver.cpp

Index: Source/modules/serviceworkers/RespondWithObserver.cpp
diff --git a/Source/modules/serviceworkers/RespondWithObserver.cpp b/Source/modules/serviceworkers/RespondWithObserver.cpp
index d5dc9e0e9faaa6161ecacf38d5b41db2f2aed210..0b5cd349e03c0b7a077fc9d4afd084a18046ffd6 100644
--- a/Source/modules/serviceworkers/RespondWithObserver.cpp
+++ b/Source/modules/serviceworkers/RespondWithObserver.cpp
@@ -203,7 +203,7 @@ void RespondWithObserver::responseWasFulfilled(const ScriptValue& value)
     }
     response->lockBody(Body::PassBody);
     if (BodyStreamBuffer* buffer = response->internalBuffer()) {
-        if (buffer == response->buffer() && response->streamAccessed())
+        if (buffer == response->buffer() && response->isBodyConsumed())
             buffer = response->createDrainingStream();
         WebServiceWorkerResponse webResponse;
         response->populateWebServiceWorkerResponse(webResponse);