Use OrderedHashTables as the backing store of JSSet and JSMap

Use OrderedHashTables as the backing store of JSSet and JSMap

This also deletes ObjectHashSet as it's no longer used.

BUG=v8:1793
LOG=N
R=mstarzinger@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=20585

[Michael Starzinger, 2014-04-07 12:37:31]

LGTM. Just one comment.

https://codereview.chromium.org/225183009/diff/1/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/225183009/diff/1/src/objects.h#newcode1080
src/objects.h:1080: V(OrderedHashTable)                          \
Since the OrderedHashTable is just the abstract super-class of the
OrderedHashSet and OrderedHashMap, we really shouldn't have three instance types
here.

I am fine with sharing one map for both OrderedHashSet and OrderedHashMap as the
CL does right now. But then we should only add one new instance type for now and
drop the unused ones.

[adamk, 2014-04-07 23:50:01]

https://codereview.chromium.org/225183009/diff/1/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/225183009/diff/1/src/objects.h#newcode1080
src/objects.h:1080: V(OrderedHashTable)                          \
On 2014/04/07 12:37:31, Michael Starzinger wrote:
> Since the OrderedHashTable is just the abstract super-class of the
> OrderedHashSet and OrderedHashMap, we really shouldn't have three instance
types
> here.
> 
> I am fine with sharing one map for both OrderedHashSet and OrderedHashMap as
the
> CL does right now. But then we should only add one new instance type for now
and
> drop the unused ones.

Okay, I switched back (only downside was that I have to keep my own custom
cast() methods).

[adamk, 2014-04-08 20:06:44]

Committed patchset #2 manually as r20585 (presubmit successful).