The comparator was actually a <= operator, while sort requires a
strict < operator. This was causing a potential assertion failure.

Bug report from Kerim Borchaev.

BUG=angle:742

Change-Id: I37c2925ab0b85e70ee1b2be3c72c6ddc062e8d28
Reviewed-on: https://chromium-review.googlesource.com/218506Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>