Remove NavigationURLLoaderImpl::OnComplete net::OK case.

NavigationURLLoaderImpl::OnComplete has code to handle a status of
net::OK. The NetworkService itself will never call
URLLoader::OnComplete with net::OK without calling OnReceiveResponse
first. When OnReceiveResponse is called, the URLLoaderClient is unbound
from the NavigationURLLoaderImpl, so OnComplete must never be received
after that.

Bug: 936962, 873269
Change-Id: I28e557850a3b1bd6b24ae2f6203b9090b2ac09bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1503133
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638052}
2 files changed