Migrate Chrome OS to histogram_macros.h includes.

Updates ifdef in histogram.h to prevent this from regressing for
Chrome OS. The ifdef will be updated incrementally as each platform
becomes fully migrated.

BUG=416479
[email protected],[email protected],[email protected]

Review-Url: https://codereview.chromium.org/2651643003
Cr-Commit-Position: refs/heads/master@{#446126}
28 files changed