Check and clear date cache in DateCurrentTime, DateLocalTimezone and getTimezoneOffset.

Check and clear date cache in DateCurrentTime, DateLocalTimezone and getTimezoneOffset.

BUG=142141
LOG=Y
R=rossberg@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19711

[ulan, 2014-02-20 14:04:59]

PTAL

[tfarina, 2014-02-20 17:58:46]

https://codereview.chromium.org/173793002/diff/40001/src/date.h
File src/date.h (right):

https://codereview.chromium.org/173793002/diff/40001/src/date.h#newcode125
src/date.h:125: void CheckTimezone() {
looks like you follow surround code and inlined the implementation in the header
file.

Is that better? Does it generate better code? Is it cheap?

If later in time you come and change this implementation, it will recompile a
bunch of files that include date.h because you make a change in the header.
Otherwise if you implement in the source file, then just date.cc will have to be
compiled again if I'm not wrong.

[rossberg, 2014-02-25 12:00:03]

lgtm

[ulan, 2014-03-07 10:01:08]

Committed patchset #3 manually as r19711 (presubmit successful).