PartitionAlloc: simplify PartitionPage structure some more.

PartitionAlloc: simplify PartitionPage structure some more.

Two important simplifications:
1) Remove the foul union. It isn't necessary if we don't try and put pages on
the active and free lists at the same time. Instead, we can simply tag free
pages as free and mop them up when we next walk the active pages list.
2) Remove the flags field. It's strictly a duplication of information we have
available in other fields. And we hate duplication because it will get out of
sync and cause bugs.
Also, the freed up field can likely be profitably used to avoid having to
re-introduce a union later.

BUG=332282
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165036

[Tom Sepez, 2014-01-13 18:15:55]

LGTM with nit.

https://codereview.chromium.org/136333002/diff/1/Source/wtf/PartitionAlloc.h
File Source/wtf/PartitionAlloc.h (right):

https://codereview.chromium.org/136333002/diff/1/Source/wtf/PartitionAlloc.h#...
Source/wtf/PartitionAlloc.h:227: PartitionPage* next;
nit: nextPage or some such.  Too many lists to simply have a next variable.

[Chris Evans, 2014-01-13 20:45:00]

On 2014/01/13 18:15:55, Tom Sepez wrote:
> LGTM with nit.
> 
> https://codereview.chromium.org/136333002/diff/1/Source/wtf/PartitionAlloc.h
> File Source/wtf/PartitionAlloc.h (right):
> 
>
https://codereview.chromium.org/136333002/diff/1/Source/wtf/PartitionAlloc.h#...
> Source/wtf/PartitionAlloc.h:227: PartitionPage* next;
> nit: nextPage or some such.  Too many lists to simply have a next variable.

nextPage sounds good, I'll do that.

[commit-bot: I haz the power, 2014-01-13 20:55:56]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cevans@chromium.org/136333002/80001

[commit-bot: I haz the power, 2014-01-13 22:00:40]

Retried try job too often on linux_blink_rel for step(s)
blink_platform_unittests, webkit_lint, webkit_python_tests, webkit_tests,
webkit_unit_tests, wtf_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_blin...

[commit-bot: I haz the power, 2014-01-13 22:05:17]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cevans@chromium.org/136333002/80001

[commit-bot: I haz the power, 2014-01-13 22:54:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cevans@chromium.org/136333002/270001

[commit-bot: I haz the power, 2014-01-14 05:09:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cevans@chromium.org/136333002/360001

[commit-bot: I haz the power, 2014-01-14 07:58:43]

Change committed as 165036