Implement PersistentValueVector, analogous to PersistentValueMap.

Implement PersistentValueVector, analogous to PersistentValueMap.

BUG=
R=dcarney@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=20341

[vogelheim, 2014-03-28 17:02:09]

First implementation of PersistentValueVector.

Q: This vector is rather simple and provides only the functionality that the
current [vV]ector<UnsafePersistent> need. In particular it doesn't bother with
weak references or iterators, find, etc., since all the current call sites need
are Append/somehow-get-all-values/Clear. One could certainly build a better
vector if we'd find that useful... Please let me know what you think.

[dcarney, 2014-03-31 09:49:58]

On 2014/03/28 17:02:09, vogelheim wrote:
> First implementation of PersistentValueVector.
> 
> Q: This vector is rather simple and provides only the functionality that the
> current [vV]ector<UnsafePersistent> need. In particular it doesn't bother with
> weak references or iterators, find, etc., since all the current call sites
need
> are Append/somehow-get-all-values/Clear. One could certainly build a better
> vector if we'd find that useful... Please let me know what you think.

lgtm, let's just go with this for now
if embedders need it, we can sweep through chrome to fix

[dcarney, 2014-03-31 10:03:59]

Committed patchset #1 manually as r20341 (presubmit successful).