[gin] Add a v8::Platform implementation to allow for v8 posting tasks

[gin] Add a v8::Platform implementation to allow for v8 posting tasks

This currently has no effect unless concurrent sweeping and job based
sweeping is turned on in v8.

BUG=v8:3015
R=abarth@chromium.org,dcarney@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=261872

[dcarney, 2014-04-04 11:23:21]

lgtm

[abarth-chromium, 2014-04-04 16:45:43]

lgtm

[jochen (gone - plz use gerrit), 2014-04-04 17:00:46]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-04-04 17:00:51]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jochen@chromium.org/225413004/20001

[commit-bot: I haz the power, 2014-04-04 17:44:27]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-04 17:44:28]

Try jobs failed on following builders:
  tryserver.chromium on win_chromium_compile_dbg

[jochen (gone - plz use gerrit), 2014-04-04 18:34:54]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-04-04 18:35:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jochen@chromium.org/225413004/40001

[commit-bot: I haz the power, 2014-04-04 21:09:22]

Change committed as 261872

[tfarina, 2014-04-05 03:42:12]

https://codereview.chromium.org/225413004/diff/40001/gin/public/v8_platform.h
File gin/public/v8_platform.h (right):

https://codereview.chromium.org/225413004/diff/40001/gin/public/v8_platform.h...
gin/public/v8_platform.h:8: #include "base/basictypes.h"
super-tiny-nit: this should have been base/macros.h :)