Revert of Last_n: Delete previously saved snapshot when navigating.

Revert of Last_n: Delete previously saved snapshot when navigating. (patchset #3 id:40001 of https://codereview.chromium.org/2824623002/ )

Reason for revert:
This test has been crashing:
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/41841/steps/chrome_public_test_apk%20on%20Android
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/41844/steps/chrome_public_test_apk%20on%20Android


Original issue's description:
> Last_n: Delete previously saved snapshot when navigating.
> 
> After the switch that made last_n use tab hidden events to trigger the creation
> of snapshots a privacy bug was introduced. Saved pages were deleted along with
> the creation of a new snapshot, what happened only on the next hide event. If
> that never happened before the device would go offline, navigating back would
> eventually present the last snapshotted page, potentially from many history
> steps ago.
> 
> This change fixes this bug by storing information about the last successful
> last_n snapshot (just like it's already done for downloads requests) and using
> the offline_id of the previous saved page to delete it upon new navigations.
> Unit tests were updated to comply with this behavior change and new integration
> tests were added to enforce the privacy requirements IRT snapshot deletion.
> 
> BUG=711770
> 
> Review-Url: https://codereview.chromium.org/2824623002
> Cr-Commit-Position: refs/heads/master@{#465459}
> Committed: https://chromium.googlesource.com/chromium/src/+/0540bc797b12c1ee7d6f648b1502a8a61dc30b8c

TBR=dewittj@chromium.org,agrieve@chromium.org,carlosk@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=711770
Review-Url: https://codereview.chromium.org/2825973002
Cr-Commit-Position: refs/heads/master@{#465500}
Committed: https://chromium.googlesource.com/chromium/src/+/da7280f6fb27c1dc22f19da890f5f227a0770b00

[aboxhall, 2017-04-19 05:40:01]

The CQ bit was checked by aboxhall@chromium.org

[aboxhall, 2017-04-19 05:40:02]

Created Revert of Last_n: Delete previously saved snapshot when navigating.

[commit-bot: I haz the power, 2017-04-19 05:40:27]

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, 2017-04-19 05:40:49]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492580401392250, "parent_rev":
"cb1b13c2139eac564415e378055d5934207635ff", "commit_rev":
"da7280f6fb27c1dc22f19da890f5f227a0770b00"}

[commit-bot: I haz the power, 2017-04-19 05:41:58]

Description was changed from

==========
Revert of Last_n: Delete previously saved snapshot when navigating. (patchset #3
id:40001 of https://codereview.chromium.org/2824623002/ )

Reason for revert:
This test has been crashing:
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Test...
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Test...


Original issue's description:
> Last_n: Delete previously saved snapshot when navigating.
> 
> After the switch that made last_n use tab hidden events to trigger the
creation
> of snapshots a privacy bug was introduced. Saved pages were deleted along with
> the creation of a new snapshot, what happened only on the next hide event. If
> that never happened before the device would go offline, navigating back would
> eventually present the last snapshotted page, potentially from many history
> steps ago.
> 
> This change fixes this bug by storing information about the last successful
> last_n snapshot (just like it's already done for downloads requests) and using
> the offline_id of the previous saved page to delete it upon new navigations.
> Unit tests were updated to comply with this behavior change and new
integration
> tests were added to enforce the privacy requirements IRT snapshot deletion.
> 
> BUG=711770
> 
> Review-Url: https://codereview.chromium.org/2824623002
> Cr-Commit-Position: refs/heads/master@{#465459}
> Committed:
https://chromium.googlesource.com/chromium/src/+/0540bc797b12c1ee7d6f648b1502...

TBR=dewittj@chromium.org,agrieve@chromium.org,carlosk@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=711770
==========

to

==========
Revert of Last_n: Delete previously saved snapshot when navigating. (patchset #3
id:40001 of https://codereview.chromium.org/2824623002/ )

Reason for revert:
This test has been crashing:
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Test...
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Test...


Original issue's description:
> Last_n: Delete previously saved snapshot when navigating.
> 
> After the switch that made last_n use tab hidden events to trigger the
creation
> of snapshots a privacy bug was introduced. Saved pages were deleted along with
> the creation of a new snapshot, what happened only on the next hide event. If
> that never happened before the device would go offline, navigating back would
> eventually present the last snapshotted page, potentially from many history
> steps ago.
> 
> This change fixes this bug by storing information about the last successful
> last_n snapshot (just like it's already done for downloads requests) and using
> the offline_id of the previous saved page to delete it upon new navigations.
> Unit tests were updated to comply with this behavior change and new
integration
> tests were added to enforce the privacy requirements IRT snapshot deletion.
> 
> BUG=711770
> 
> Review-Url: https://codereview.chromium.org/2824623002
> Cr-Commit-Position: refs/heads/master@{#465459}
> Committed:
https://chromium.googlesource.com/chromium/src/+/0540bc797b12c1ee7d6f648b1502...

TBR=dewittj@chromium.org,agrieve@chromium.org,carlosk@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=711770

Review-Url: https://codereview.chromium.org/2825973002
Cr-Commit-Position: refs/heads/master@{#465500}
Committed:
https://chromium.googlesource.com/chromium/src/+/da7280f6fb27c1dc22f19da890f5...
==========

[commit-bot: I haz the power, 2017-04-19 05:41:59]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/da7280f6fb27c1dc22f19da890f5...