Remove most null-checks of ViewsDelegate::GetInstance().

The only remaining ones are during initialization.

Bug: 691894
Change-Id: Iafc6feeb125968fd60a0fc51281843f85c1c133a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1610706
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659382}
23 files changed