Revert of Reland v3 of Session refactor

Revert of Reland v3 of Session refactor (patchset #5 id:70001 of https://codereview.chromium.org/2651583006/ )

Reason for revert:
crbug.com/686620

Original issue's description:
> Reland v3 of Session refactor
> 
> Original CL review: https://codereview.chromium.org/2494533002
> 
> This relands that CL, with a couple key fixes:
> - Detect if a previously synced tab no longer exists, and ignore it if so
> - Simplifies the logic to add tab ids to a window to avoid possibly out-of-bounds
> - Adds checking for invalid tab node ids
> - Simplifies the logic that either calls AssociateTab or AssociateRestoredPlaceholderTab
> - Adds some CHECKs to help detect remaining issues.
> 
> BUG=639009, 673618
> 
> Review-Url: https://codereview.chromium.org/2651583006
> Cr-Commit-Position: refs/heads/master@{#446405}
> Committed: https://chromium.googlesource.com/chromium/src/+/0b0a0a13587273010f58db836c86c0d4748e9e5b

TBR=skym@chromium.org,pnoland@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=639009, 673618
Review-Url: https://codereview.chromium.org/2664023002
Cr-Commit-Position: refs/heads/master@{#447145}
Committed: https://chromium.googlesource.com/chromium/src/+/ddd430086336c26c832f8a4f80c6f595d5f61a10

[Nicolas Zea, 2017-01-30 23:59:26]

The CQ bit was checked by zea@chromium.org

[Nicolas Zea, 2017-01-30 23:59:26]

Created Revert of Reland v3 of Session refactor

[commit-bot: I haz the power, 2017-01-30 23:59:57]

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

[skym, 2017-01-31 00:14:28]

lgtm

[commit-bot: I haz the power, 2017-01-31 01:00:43]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1485820766088610, "parent_rev":
"23b834b62f73bac4ccd42171a9b496d9c1b0829b", "commit_rev":
"ddd430086336c26c832f8a4f80c6f595d5f61a10"}

[commit-bot: I haz the power, 2017-01-31 01:01:21]

Description was changed from

==========
Revert of Reland v3 of Session refactor (patchset #5 id:70001 of
https://codereview.chromium.org/2651583006/ )

Reason for revert:
crbug.com/686620

Original issue's description:
> Reland v3 of Session refactor
> 
> Original CL review: https://codereview.chromium.org/2494533002
> 
> This relands that CL, with a couple key fixes:
> - Detect if a previously synced tab no longer exists, and ignore it if so
> - Simplifies the logic to add tab ids to a window to avoid possibly
out-of-bounds
> - Adds checking for invalid tab node ids
> - Simplifies the logic that either calls AssociateTab or
AssociateRestoredPlaceholderTab
> - Adds some CHECKs to help detect remaining issues.
> 
> BUG=639009, 673618
> 
> Review-Url: https://codereview.chromium.org/2651583006
> Cr-Commit-Position: refs/heads/master@{#446405}
> Committed:
https://chromium.googlesource.com/chromium/src/+/0b0a0a13587273010f58db836c86...

TBR=skym@chromium.org,pnoland@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=639009, 673618
==========

to

==========
Revert of Reland v3 of Session refactor (patchset #5 id:70001 of
https://codereview.chromium.org/2651583006/ )

Reason for revert:
crbug.com/686620

Original issue's description:
> Reland v3 of Session refactor
> 
> Original CL review: https://codereview.chromium.org/2494533002
> 
> This relands that CL, with a couple key fixes:
> - Detect if a previously synced tab no longer exists, and ignore it if so
> - Simplifies the logic to add tab ids to a window to avoid possibly
out-of-bounds
> - Adds checking for invalid tab node ids
> - Simplifies the logic that either calls AssociateTab or
AssociateRestoredPlaceholderTab
> - Adds some CHECKs to help detect remaining issues.
> 
> BUG=639009, 673618
> 
> Review-Url: https://codereview.chromium.org/2651583006
> Cr-Commit-Position: refs/heads/master@{#446405}
> Committed:
https://chromium.googlesource.com/chromium/src/+/0b0a0a13587273010f58db836c86...

TBR=skym@chromium.org,pnoland@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=639009, 673618

Review-Url: https://codereview.chromium.org/2664023002
Cr-Commit-Position: refs/heads/master@{#447145}
Committed:
https://chromium.googlesource.com/chromium/src/+/ddd430086336c26c832f8a4f80c6...
==========

[commit-bot: I haz the power, 2017-01-31 01:01:22]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/ddd430086336c26c832f8a4f80c6...