The maximum length of the chars in bytes was hardcoded and was not
updated with the increase in string length on 64-bit platforms.
The other platforms don't do this debug check so they don't need
updating.

Bug: chromium:779407
Change-Id: I94fd946f9e67b39075c1f7eed14a20e9db126a72
Reviewed-on: https://chromium-review.googlesource.com/753584Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49142}