Replace View::has_children() with children().empty().

These have the opposite meaning, so callers have to be negated.

Bug: 940135
Change-Id: I99f01b8a6f05b1ba0b031d4cb4e573dce9ba54ad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1526668
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642076}
34 files changed