Don't clear DNS cache when closing last incognito Window.

The DNS cache is now a per-NetworkContext cache, instead of a global,
so clearing the cache when closing incognito is no longer useful -
destroying the incognito profile will destroy its own DNS cache.

Bug: 1042354
Change-Id: Ib3fd2dc03cf48ca1ca1d1fd7fca025fccb2a4a2c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003212
Reviewed-by: Eric Orth <ericorth@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732622}
2 files changed