Make sure that post-interceptor property getter doesn't assume name lookup is...

Make sure that post-interceptor property getter doesn't assume name lookup is enough.

R=ager
TEST=none
BUG=20104

[antonm, 2010-02-18 07:53:41]

Dmitry, may you add v8 reduction for this fix?

[Mads Ager (chromium), 2010-02-18 08:29:30]

Dimitri, can I steal this bug?  The result.IsValid() check should have been
enough to ensure that there is a local property here, so I'm pretty sure the
problem is in LocalLookupRealNamedProperty instead.

I'll fix it and add regression tests to the V8 test suite.

http://codereview.chromium.org/629008/diff/1/2
File src/objects.cc (right):

http://codereview.chromium.org/629008/diff/1/2#newcode6175
src/objects.cc:6175: // Successful name lookup doesn't mean the value is there,
because the
There is something fishy going on here.  The result.IsValid() check should make
sure that there actually is a property on the object.

[Mads Ager (chromium), 2010-02-18 13:13:14]

The real problem here is that we test for IsValid instead of testing for
IsProperty.  I have cleaned up the use of the LookupResult class and added a
regression test for the issue in this change: 

http://codereview.chromium.org/647015