Comment on attachment 8834012 [details] [diff] [review] file_xhr.patch Some explanation about what the patch is doing would have been really nice. Now I just had to read it through several times. >+GetLocalFileFromChannel(nsIRequest *request, nsIFile** aFile) Nit, nsIRequest* aRequest >+DummyStreamReaderFunc(nsIInputStream* aInputStream, >+ void* aClosure, >+ const char* aFromRawSegment, >+ uint32_t aToOffset, >+ uint32_t aCount, >+ uint32_t *aWriteCount) uint32_t* aWriteCount >+ ErrorResult error; >+ RefPtr<Promise> promise = >+ FileCreatorHelper::CreateFile(global, file, bag, true, error); >+ if (NS_WARN_IF(error.Failed())) { >+ return error.StealNSResult(); >+ } >+ >+ FileCreationHandler::Create(promise, this); >+ waitingForBlobCreation = true; >+ return NS_OK; Why you set waitingForBlobCreation to true right before returning? >+ // We stream data to mBlobStorage when response type is "moz-blob". > nsAutoPtr<BlobSet> mBlobSet; The comment talks about mBlobStorage but the variable name is mBlobSet I hope we have tests for this. Please ensure that. Tests which run in e10s mode too.

Pushed by amarchesini@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/a75a77d1bb99 XHR should create a Blob in the parent process when run from a file:// URL, r=smaug