Compare function for std::sort should satisfy strict weak ordering
relation.

BUG=chromium:696251

Change-Id: I1c07e3bb1b012fd203bc059a21a75ae0fc61f5ac
Reviewed-on: https://chromium-review.googlesource.com/447036Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43446}