Make __DATE__ and __TIME__ to evaluate to an empty string.

If __DATE__ or __TIME__ used in code, current date or time will be
filled.  Such a value may change compile by compile, and breaks
deterministic build.

BUG=314403

Review-Url: https://codereview.chromium.org/2255093004
Cr-Commit-Position: refs/heads/master@{#414018}
1 file changed