First phase of migration to new named property query callbacks.

First phase of migration to new named property query callbacks.

Eventually named property query callbacks will return attributes
(as an integer) or an empty handle if property is not intercepted.

To gradually migrate to this new API, USE_NEW_QUERY_CALLBACK
macro would control if old or new style API is used.

So the migration plan is:

1) introduce new API which should be explictily enabled;
2) switch to new API defining USE_NEW_QUERY_CALLBACK before
  include of <v8.h> (that would require changes to client code as well)
3) remove old API from v8
4) remove #define USE_NEW_QUERY_CALLBACK from clients.

Committed: http://code.google.com/p/v8/source/detail?r=4797

[antonm, 2010-06-04 10:15:03]

Mads,

may you have a look?

The main incompatible change is omission of v8::False return values.

And if you could suggest how to make it in more elegant way, that'd be most
appreciated.

[Mads Ager (chromium), 2010-06-04 11:36:15]

LGTM

Let's make the transition period as short as possible on this!