Purge session storage caches on memory pressure

Purge session storage caches on memory pressure

The session storage caches are never cleared because the namespace
assumes that backing is only file based. The session storage is backed
by leveldb database.
This change would not accidently delete storage since
DOMStorageArea::PurgeMemory also checks if backing is present and commit
tasks are done before purging.

BUG=696112
Review-Url: https://codereview.chromium.org/2717843002
Cr-Commit-Position: refs/heads/master@{#453403}
Committed: https://chromium.googlesource.com/chromium/src/+/c72ce2a231f22abab37a62e41f15a79545ba4cce

[ssid, 2017-02-25 02:23:23]

ssid@chromium.org changed reviewers:
+ mek@chromium.org, michaeln@chromium.org

[ssid, 2017-02-25 02:23:24]

ptal, thanks

[ssid, 2017-02-25 02:25:44]

The CQ bit was checked by ssid@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-02-25 02:26:01]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-25 03:11:49]

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

[commit-bot: I haz the power, 2017-02-25 03:11:50]

Dry run: This issue passed the CQ dry run.

[Marijn Kruisselbrink, 2017-02-27 22:02:08]

good catch, lgtm

[ssid, 2017-02-27 22:24:42]

The CQ bit was checked by ssid@chromium.org

[commit-bot: I haz the power, 2017-02-27 22:25:18]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-28 00:07:27]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1488234282956240, "parent_rev":
"b4016a52a030882fc8a55e847fe3d0fa139be634", "commit_rev":
"c72ce2a231f22abab37a62e41f15a79545ba4cce"}

[commit-bot: I haz the power, 2017-02-28 00:08:09]

Description was changed from

==========
Purge session storage caches on memory pressure

The session storage caches are never cleared because the namespace
assumes that backing is only file based. The session storage is backed
by leveldb database.
This change would not accidently delete storage since
DOMStorageArea::PurgeMemory also checks if backing is present and commit
tasks are done before purging.

BUG=696112
==========

to

==========
Purge session storage caches on memory pressure

The session storage caches are never cleared because the namespace
assumes that backing is only file based. The session storage is backed
by leveldb database.
This change would not accidently delete storage since
DOMStorageArea::PurgeMemory also checks if backing is present and commit
tasks are done before purging.

BUG=696112

Review-Url: https://codereview.chromium.org/2717843002
Cr-Commit-Position: refs/heads/master@{#453403}
Committed:
https://chromium.googlesource.com/chromium/src/+/c72ce2a231f22abab37a62e41f15...
==========

[commit-bot: I haz the power, 2017-02-28 00:08:10]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/c72ce2a231f22abab37a62e41f15...