Due to a bug in gcc<5, we could not make some arrays constexpr. This CL
fixes this by encapsulating the respective functions in functors.

R=tebbi@chromium.org

Change-Id: I9947e38f7fd9b801f85623663849699c0f8ffd75
Reviewed-on: https://chromium-review.googlesource.com/730303
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48779}