The Size() includes the page header.

Bug: chromium:852420
Change-Id: I1f2da2309ff38f2222c82b5758937bdaf5036f12
Reviewed-on: https://chromium-review.googlesource.com/c/1458242Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59438}