Network traffic annotation added to extensions::image_writer::WriteFromUrlOperation.

Network traffic annotation is added to network request of extensions::image_writer::WriteFromUrlOperation.

BUG=656607

Review-Url: https://codereview.chromium.org/2691963002
Cr-Commit-Position: refs/heads/master@{#451456}
void WriteFromUrlOperation::OnURLFetchComplete(const net::URLFetcher* source) {
  DCHECK_CURRENTLY_ON(BrowserThread::FILE);

  if (source->GetStatus().is_success() && source->GetResponseCode() == 200) {
    SetProgress(kProgressComplete);

    download_continuation_.Run();

    download_continuation_ = base::Closure();
  } else {
    Error(error::kDownloadInterrupted);
  }
}

void WriteFromUrlOperation::OnURLFetchComplete(const net::URLFetcher* source) {
  DCHECK_CURRENTLY_ON(BrowserThread::FILE);

  if (source->GetStatus().is_success() && source->GetResponseCode() == 200) {
    SetProgress(kProgressComplete);

    download_continuation_.Run();

    download_continuation_ = base::Closure();
  } else {
    Error(error::kDownloadInterrupted);
  }
}
