Reland of cc : Make LayerImpl destruction independent of tree hierarchy

Reland of cc : Make LayerImpl destruction independent of tree hierarchy (patchset #1 id:1 of https://codereview.chromium.org/2044253004/ )

Reason for revert:
around and around we go :D

Original issue's description:
> Revert of cc : Make LayerImpl destruction independent of tree hierarchy (patchset #2 id:20001 of https://codereview.chromium.org/2043963005/ )
>
> Reason for revert:
> Didn't fix anything.
>
> Original issue's description:
> > cc : Make LayerImpl destruction independent of tree hierarchy
> >
> > Instead of deleting all layers when the root is deleted, we delete
> > all layers when the layer tree impl is shutdown.
> >
> > BUG=617791
> > CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
> >
> > Committed: https://crrev.com/e536d2292fa548ee6231ff23ac65203c261e4a14
> > Cr-Commit-Position: refs/heads/master@{#398606}
>
> TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=617791
>
> Committed: https://crrev.com/ef1625ae9feafee9ddaa2a58b9476175d7956b8b
> Cr-Commit-Position: refs/heads/master@{#398633}

TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=617791
Committed: https://crrev.com/2176f9255c324d96d8d980ccfae345225cee1872
Cr-Commit-Position: refs/heads/master@{#398637}

[Ken Rockot(use gerrit already), 2016-06-08 19:16:00]

The CQ bit was checked by rockot@chromium.org

[Ken Rockot(use gerrit already), 2016-06-08 19:16:00]

Created Reland of cc : Make LayerImpl destruction independent of tree hierarchy

[commit-bot: I haz the power, 2016-06-08 19:16:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2049883002/1

[commit-bot: I haz the power, 2016-06-08 19:18:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-08 19:22:25]

Description was changed from

==========
Reland of cc : Make LayerImpl destruction independent of tree hierarchy
(patchset #1 id:1 of https://codereview.chromium.org/2044253004/ )

Reason for revert:
around and around we go :D

Original issue's description:
> Revert of cc : Make LayerImpl destruction independent of tree hierarchy
(patchset #2 id:20001 of https://codereview.chromium.org/2043963005/ )
> 
> Reason for revert:
> Didn't fix anything.
> 
> Original issue's description:
> > cc : Make LayerImpl destruction independent of tree hierarchy
> >
> > Instead of deleting all layers when the root is deleted, we delete
> > all layers when the layer tree impl is shutdown.
> >
> > BUG=617791
> > CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
> >
> > Committed: https://crrev.com/e536d2292fa548ee6231ff23ac65203c261e4a14
> > Cr-Commit-Position: refs/heads/master@{#398606}
> 
> TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=617791
> 
> Committed: https://crrev.com/ef1625ae9feafee9ddaa2a58b9476175d7956b8b
> Cr-Commit-Position: refs/heads/master@{#398633}

TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=617791
==========

to

==========
Reland of cc : Make LayerImpl destruction independent of tree hierarchy
(patchset #1 id:1 of https://codereview.chromium.org/2044253004/ )

Reason for revert:
around and around we go :D

Original issue's description:
> Revert of cc : Make LayerImpl destruction independent of tree hierarchy
(patchset #2 id:20001 of https://codereview.chromium.org/2043963005/ )
>
> Reason for revert:
> Didn't fix anything.
>
> Original issue's description:
> > cc : Make LayerImpl destruction independent of tree hierarchy
> >
> > Instead of deleting all layers when the root is deleted, we delete
> > all layers when the layer tree impl is shutdown.
> >
> > BUG=617791
> > CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
> >
> > Committed: https://crrev.com/e536d2292fa548ee6231ff23ac65203c261e4a14
> > Cr-Commit-Position: refs/heads/master@{#398606}
>
> TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=617791
>
> Committed: https://crrev.com/ef1625ae9feafee9ddaa2a58b9476175d7956b8b
> Cr-Commit-Position: refs/heads/master@{#398633}

TBR=ajuma@chromium.org,weiliangc@chromium.org,jaydasika@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=617791

Committed: https://crrev.com/2176f9255c324d96d8d980ccfae345225cee1872
Cr-Commit-Position: refs/heads/master@{#398637}
==========

[commit-bot: I haz the power, 2016-06-08 19:22:26]

Patchset 1 (id:??) landed as
https://crrev.com/2176f9255c324d96d8d980ccfae345225cee1872
Cr-Commit-Position: refs/heads/master@{#398637}