GitLab

Add the logic to update visibility for "Clear all" button depends on the
count of total and unpinned notification.

BUG=1111167

Change-Id: Ie609ae1225c0041e3c45815b1f4c2550136ace77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2339942
Commit-Queue: Andre Le <leandre@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799890}