The previous method was too brittle as applying a variable number of arguments to Date can be manipulated in too many ways, e.g. concat and apply semantics.

The new method shoud suffice for most cases.

BUG=chromium:698305
NOTRY=true
TBR=yangguo@chromium.org,mstarzinger@chromium.org

Change-Id: If6baf6ca8f1534c41ab8c50a5c507df89fbf0d16
Reviewed-on: https://chromium-review.googlesource.com/449653Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43601}