PartitionAlloc: Add a lock to Partitions::initialize()

PartitionAlloc: Add a lock to Partitions::initialize()

It is possible that multiple threads contend with initializing Partitions.
We need to acquire a lock before doing the initialization.

BUG=508700
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198825

[haraken, 2015-07-13 00:51:43]

haraken@chromium.org changed reviewers:
+ bashi@chromium.org, cevans@chromium.org

[haraken, 2015-07-13 00:51:43]

PTAL.

It seems my previous comment (https://codereview.chromium.org/1190883003/#msg5)
was wrong.

[bashi, 2015-07-13 23:27:10]

non-owner LGTM

[haraken, 2015-07-13 23:32:08]

haraken@chromium.org changed reviewers:
+ tkent@chromium.org

[haraken, 2015-07-13 23:32:08]

+tkent-san: Mind taking a look as an owner?

[tkent, 2015-07-14 00:42:36]

https://codereview.chromium.org/1234823002/diff/1/Source/wtf/Partitions.h
File Source/wtf/Partitions.h (right):

https://codereview.chromium.org/1234823002/diff/1/Source/wtf/Partitions.h#new...
Source/wtf/Partitions.h:102: static int s_lock;
let's give more descriptive name.  e.g. s_initializationLock

[haraken, 2015-07-14 00:51:25]

On 2015/07/14 00:42:36, tkent wrote:
> https://codereview.chromium.org/1234823002/diff/1/Source/wtf/Partitions.h
> File Source/wtf/Partitions.h (right):
> 
>
https://codereview.chromium.org/1234823002/diff/1/Source/wtf/Partitions.h#new...
> Source/wtf/Partitions.h:102: static int s_lock;
> let's give more descriptive name.  e.g. s_initializationLock

Done.

[tkent, 2015-07-14 01:08:07]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-07-14 01:08:07]

lgtm

[tkent, 2015-07-14 01:08:07]

The patchset sent to the CQ was uploaded after l-g-t-m from bashi@chromium.org
Link to the patchset: https://codereview.chromium.org/1234823002/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-07-14 01:08:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1234823002/20001

[commit-bot: I haz the power, 2015-07-14 02:11:33]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198825