Deprecate goog.now.
Deprecate goog.now.

RELNOTES: goog.now is now deprecated in favor of Date.now

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=267248795

lucidsoftware/closure-library,google/closure-library,lucidsoftware/closure-library,lucidsoftware/closure-library,google/closure-library,google/closure-library,google/closure-library,google/closure-library,lucidsoftware/closure-library