Add an API for enumerating persistent handles

Add an API for enumerating persistent handles

This API lets the embedder enumerate handles that have class ids. WebKit will
use this feature during garbage collection to compute object groups for DOM
nodes. Previously, we kept a list of DOM nodes on the WebKit side, but that
list is redundant with the global handles list in V8.

Committed: https://code.google.com/p/v8/source/detail?r=12750

[abarth-chromium, 2012-10-16 23:12:58]

This patch is a work-in-progress.  I'm working on the WebKit side of the change
now to verify that this is actually a win.

[abarth-chromium, 2012-10-17 05:42:05]

Ok, this is ready for review.  I've also added some accessors that are useful
for writing ASSERTs that this code is working as expected.  I can break those
out into a separate change if you'd prefer.

Thanks!

[abarth-chromium, 2012-10-17 06:09:31]

If you're interested, you can see the WebKit side of this work in
https://github.com/abarth/webkit/compare/master...newgc

[Michael Starzinger, 2012-10-17 08:47:47]

This is looking good. Just some minor nits. Unfortunately I will be OOO until
next week. I'll give this to Sven so he can land it for you.

https://codereview.chromium.org/11190011/diff/12001/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/11190011/diff/12001/include/v8.h#newcode405
include/v8.h:405: inline bool IsIndependent() const;
Add short one-liner comment about this function.

https://codereview.chromium.org/11190011/diff/12001/include/v8.h#newcode422
include/v8.h:422: inline uint16_t WrapperClassId() const;
Either adapt the above comment to cover both functions or add separate comment
for the getter.

https://codereview.chromium.org/11190011/diff/12001/include/v8.h#newcode3017
include/v8.h:3017: * Interface for iterating though all external resources in
the heap.
s/though/through/

https://codereview.chromium.org/11190011/diff/12001/include/v8.h#newcode3027
include/v8.h:3027: * Interface for iterating though the persistent handles in
the heap.
s/though the/through all/

[abarth-chromium, 2012-10-17 18:45:45]

I've uploaded a new version of the patch that addresses all reviewer feedback
and adds some API tests.

Thanks!

[Sven Panne, 2012-10-18 06:40:03]

LGTM, landing...

P.S.: Please use bleeding_edge as the base URL for patches.

[abarth-chromium, 2012-10-18 16:32:30]

On 2012/10/18 06:40:03, Sven Panne wrote:
> LGTM, landing...

Thanks!

> P.S.: Please use bleeding_edge as the base URL for patches.

Will do.