[WebURLLoaderImpl] Reset response body synchronously on cancel

WebURLLoaderImpl is not destructed when the request is cancelled, so
it's better to destruct the response body handle in
WebURLLoaderImpl::Context::Cancel manually.

Bug: 894819, 927184, 929793
Change-Id: I12a5c916ff64ecbdeb8013cff88c95bd111c31ab
Reviewed-on: https://chromium-review.googlesource.com/c/1480308
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Auto-Submit: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634112}
1 file changed