GitLab

Nukes LayoutItems and folds into Layout as that is the only place
calling into it. Removes early out if parent() is NULL in Layout. No
point in doing that.

BUG=416641
TEST=none
R=msw@chromium.org

Review URL: https://codereview.chromium.org/656033007

Cr-Commit-Position: refs/heads/master@{#299920}