removes switches::IsNotificationIndicatorEnabled()

It's also defined/declared in features, which is what is actually used.

BUG=none
TEST=none

Change-Id: I0f2d52b18f712c51dec1ba4e78203a58e3bd771c
Reviewed-on: https://chromium-review.googlesource.com/c/1476522
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633314}
2 files changed