Don't use TLS for space iterators.

Don't use TLS for space iterators.

This is not only inherently slow, but it also forces the caller to enter an
Isolate before. Both is bad, so we have to do some heap plumbing.

BUG=v8:2531
Committed: http://code.google.com/p/v8/source/detail?r=13638

[Michael Starzinger, 2013-02-11 12:32:01]

LGTM with a nit.

https://codereview.chromium.org/12217106/diff/2001/src/heap.h
File src/heap.h (right):

https://codereview.chromium.org/12217106/diff/2001/src/heap.h#newcode2393
src/heap.h:2393: Heap* heap_;
Move this down two lines to after the method declaration.

[Sven Panne, 2013-02-11 12:50:00]

Addressed comments, checking with Chrome to see if devtools etc. still work
before landing...

https://codereview.chromium.org/12217106/diff/2001/src/heap.h
File src/heap.h (right):

https://codereview.chromium.org/12217106/diff/2001/src/heap.h#newcode2393
src/heap.h:2393: Heap* heap_;
On 2013/02/11 12:32:01, Michael Starzinger wrote:
> Move this down two lines to after the method declaration.

Done.

[Vyacheslav Egorov (Google), 2013-02-11 13:07:31]

DBC

What happens if I try to iterate spaces while the isolate is being destroyed?

(e.g. from another thread without holding an Isolate lock?)