Call CertificateRequestCompleted() in SignedExchangeCertFetcher::OnDataComplete()

We need to call CertificateRequestCompleted() in OnDataComplete() because
the SignedExchangeCertFetcher may be deleted before OnComplete() is called.

Bug: 941364
Change-Id: I37b6909d9a9b2b57605fc45e11c2e5f33c8cfc6b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1520426
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640631}
3 files changed