Revert "Extensions: Navigate to default chrome page on extension unload"

This reverts commit 4d546d6ecc0e621a0d08f804a9e25c4427055740.

Reason for revert: this patch caused a bug where we leave extraneous
windows around when coming out of sleep.

TBR=rdevlin.cronin@chromium.org, sky@chromium.org (c/b/ui/browser - clean revert)

(cherry picked from commit f16ef54406c24f856c79546dcef4937ce580b696)

Bug: 818351
Change-Id: I3cf6d60a4588b36619dc4e461c3b8cf29722d6cd
Reviewed-on: https://chromium-review.googlesource.com/947473
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Ɓukasz Anforowicz <lukasza@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#540720}
Reviewed-on: https://chromium-review.googlesource.com/949306
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#658}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
4 files changed