Invalidate OS-specific datetime cache on configuration change notification

Invalidate OS-specific datetime cache on configuration change notification

When V8 is informed that the system's date time configuration has changed,
it should also drop its OS-specific caches of time zone information

R=ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19808

[ulan, 2014-03-11 08:56:06]

lgtm

[ulan, 2014-03-11 08:57:38]

I will land this in V8 for you.

[ulan, 2014-03-11 15:47:04]

Committed patchset #1 manually as r19808 (presubmit successful).

[jamesr, 2014-03-11 22:24:16]

Hmm, upon further thought I doubt this is threadsafe.  Consider what happens if
two workers are trying to query time zone information at the same time after the
cache has been invalidated - they'll simultaneously attempt to populate this.

[ulan, 2014-03-12 10:08:36]

On 2014/03/11 22:24:16, jamesr wrote:
> Hmm, upon further thought I doubt this is threadsafe.  Consider what happens
if
> two workers are trying to query time zone information at the same time after
the
> cache has been invalidated - they'll simultaneously attempt to populate this.

You're right! There is a race. I uploaded a CL that makes this cache per
isolate: https://codereview.chromium.org/197023002/