Add lock around modification of HostSharedBitmapManagerClient::owned_bitmaps_

Add lock around modification of HostSharedBitmapManagerClient::owned_bitmaps_

This can be modified from both the FILE and IO threads.

BUG=559865
Committed: https://crrev.com/82b5c2391ca0b3487394a2a15dc9eb97ea977c93
Cr-Commit-Position: refs/heads/master@{#361272}

[jbauman, 2015-11-24 00:35:39]

jbauman@chromium.org changed reviewers:
+ piman@chromium.org

[piman, 2015-11-24 01:39:58]

https://codereview.chromium.org/1464383004/diff/1/content/common/host_shared_...
File content/common/host_shared_bitmap_manager.cc (right):

https://codereview.chromium.org/1464383004/diff/1/content/common/host_shared_...
content/common/host_shared_bitmap_manager.cc:76: base::AutoLock lock(lock_);
Is it possible to lock only when accessing the map? This is used on the FILE
thread because arguably it takes time. We wouldn't want to block the IO thread
during that time.

[jbauman, 2015-11-24 02:42:18]

On 2015/11/24 01:39:58, piman (slow to review) wrote:
>
https://codereview.chromium.org/1464383004/diff/1/content/common/host_shared_...
> File content/common/host_shared_bitmap_manager.cc (right):
> 
>
https://codereview.chromium.org/1464383004/diff/1/content/common/host_shared_...
> content/common/host_shared_bitmap_manager.cc:76: base::AutoLock lock(lock_);
> Is it possible to lock only when accessing the map? This is used on the FILE
> thread because arguably it takes time. We wouldn't want to block the IO thread
> during that time.

Ok, done. Also added a few checks around the modifications to owned_bitmaps_ to
ensure misbehaving clients don't cause problems.

[piman, 2015-11-24 03:00:37]

lgtm

https://codereview.chromium.org/1464383004/diff/20001/content/common/host_sha...
File content/common/host_shared_bitmap_manager.cc (right):

https://codereview.chromium.org/1464383004/diff/20001/content/common/host_sha...
content/common/host_shared_bitmap_manager.cc:66: base::AutoLock lock(lock_);
nit: I think you don't need this one (only 1 thread can call this at a time).

[jbauman, 2015-11-24 04:40:34]

The CQ bit was checked by jbauman@chromium.org

[jbauman, 2015-11-24 04:40:34]

The patchset sent to the CQ was uploaded after l-g-t-m from piman@chromium.org
Link to the patchset: https://codereview.chromium.org/1464383004/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-11-24 04:42:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1464383004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1464383004/40001

[commit-bot: I haz the power, 2015-11-24 06:12:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-24 06:12:05]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[jbauman, 2015-11-24 06:15:36]

The CQ bit was checked by jbauman@chromium.org

[commit-bot: I haz the power, 2015-11-24 06:17:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1464383004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1464383004/40001

[commit-bot: I haz the power, 2015-11-24 07:43:35]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-11-24 07:44:08]

Patchset 3 (id:??) landed as
https://crrev.com/82b5c2391ca0b3487394a2a15dc9eb97ea977c93
Cr-Commit-Position: refs/heads/master@{#361272}