PepperGL: Enable client side arrays support.

PepperGL: Enable client side arrays support.

Currently, the client side arrays feature is controlled by a compile flag.
And the flag is only defined in nacl build. This change uses a variable to
control it. So we could enable it in runtime.

BUG=429179
Committed: https://crrev.com/5527fa12043d5c268b31e3744e2e03d86b7e8231
Cr-Commit-Position: refs/heads/master@{#302478}

[Peng, 2014-11-03 17:07:17]

penghuang@chromium.org changed reviewers:
+ dmichael@chromium.org, piman@chromium.org

[Peng, 2014-11-03 17:07:17]

Hi David & Antoine, PTAL. Thanks.

[piman, 2014-11-03 19:52:10]

lgtm

[dmichael (off chromium), 2014-11-03 20:06:02]

ppapi lgtm

[Peng, 2014-11-03 20:13:33]

The CQ bit was checked by penghuang@chromium.org

[commit-bot: I haz the power, 2014-11-03 20:14:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/702493002/20001

[commit-bot: I haz the power, 2014-11-03 21:05:43]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-11-03 21:06:52]

Patchset 2 (id:??) landed as
https://crrev.com/5527fa12043d5c268b31e3744e2e03d86b7e8231
Cr-Commit-Position: refs/heads/master@{#302478}