gin: Add the concept of named and indexed interceptors.

gin: Add the concept of named and indexed interceptors.

This will allow for using gin as a drop-in replacement for NPObject.

BUG=347565
R=abarth@chromium.org,dcarney@chromium.org,aa@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=256431

[jochen (gone - plz use gerrit), 2014-03-11 15:37:50]

Since the interceptors require several methods with defined signatures, I didn't
use template magic, but put the methods on interface (e.g.
gin::NamedPropertyInterceptor)

A class that wishes to use this interface needs to derive from both Wrappable
and the interface. interceptor_unittest.cc has an exhaustive example.

Since the holder is of type WrappableBase*, I maintain a mapping from
WrappableBase* to the interface pointers in the per-isolate-data and use virtual
methods to dispatch to the actual implementation.

PTAL

[abarth-chromium, 2014-03-11 18:33:20]

Neat.  LGTM

[jochen (gone - plz use gerrit), 2014-03-11 19:28:09]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-03-11 19:56:05]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jochen@chromium.org/194603003/20001

[commit-bot: I haz the power, 2014-03-11 21:53:27]

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

[commit-bot: I haz the power, 2014-03-11 21:53:28]

Try jobs failed on following builders: linux_chromium_rel

[jochen (gone - plz use gerrit), 2014-03-11 21:56:11]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-03-11 22:35:06]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jochen@chromium.org/194603003/20001

[commit-bot: I haz the power, 2014-03-12 04:59:09]

Change committed as 256431