Revert of Add DCHECK for duplicate layers with the same cc::ElementId.

Revert of Add DCHECK for duplicate layers with the same cc::ElementId. (patchset #2 id:20001 of https://codereview.chromium.org/2639103002/ )

Reason for revert:
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Mac10.11%20%28dbg%29/builds/6968

Original issue's description:
> Add DCHECK for duplicate layers with the same cc::ElementId.
> 
> BUG=673963
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
> 
> Review-Url: https://codereview.chromium.org/2639103002
> Cr-Commit-Position: refs/heads/master@{#444407}
> Committed: https://chromium.googlesource.com/chromium/src/+/f547b3e1d559fd2abd8c9ed897ab627d8e23420a

TBR=ajuma@chromium.org,skobes@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=673963
Review-Url: https://codereview.chromium.org/2646583002
Cr-Commit-Position: refs/heads/master@{#444452}
Committed: https://chromium.googlesource.com/chromium/src/+/bc1dbcfdf6fa0db6e78c6ac3af02b6d68e1e2c72

[jianli, 2017-01-18 20:04:01]

The CQ bit was checked by jianli@chromium.org

[jianli, 2017-01-18 20:04:01]

Created Revert of Add DCHECK for duplicate layers with the same cc::ElementId.

[commit-bot: I haz the power, 2017-01-18 20:04:29]

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, 2017-01-18 20:09:01]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484769841188400, "parent_rev":
"33d0fb8f91ec8be93f0bc56b63c67a9f2dcebec6", "commit_rev":
"bc1dbcfdf6fa0db6e78c6ac3af02b6d68e1e2c72"}

[commit-bot: I haz the power, 2017-01-18 20:09:39]

Description was changed from

==========
Revert of Add DCHECK for duplicate layers with the same cc::ElementId. (patchset
#2 id:20001 of https://codereview.chromium.org/2639103002/ )

Reason for revert:
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Mac1...

Original issue's description:
> Add DCHECK for duplicate layers with the same cc::ElementId.
> 
> BUG=673963
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
> 
> Review-Url: https://codereview.chromium.org/2639103002
> Cr-Commit-Position: refs/heads/master@{#444407}
> Committed:
https://chromium.googlesource.com/chromium/src/+/f547b3e1d559fd2abd8c9ed897ab...

TBR=ajuma@chromium.org,skobes@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=673963
==========

to

==========
Revert of Add DCHECK for duplicate layers with the same cc::ElementId. (patchset
#2 id:20001 of https://codereview.chromium.org/2639103002/ )

Reason for revert:
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Mac1...

Original issue's description:
> Add DCHECK for duplicate layers with the same cc::ElementId.
> 
> BUG=673963
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
> 
> Review-Url: https://codereview.chromium.org/2639103002
> Cr-Commit-Position: refs/heads/master@{#444407}
> Committed:
https://chromium.googlesource.com/chromium/src/+/f547b3e1d559fd2abd8c9ed897ab...

TBR=ajuma@chromium.org,skobes@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=673963

Review-Url: https://codereview.chromium.org/2646583002
Cr-Commit-Position: refs/heads/master@{#444452}
Committed:
https://chromium.googlesource.com/chromium/src/+/bc1dbcfdf6fa0db6e78c6ac3af02...
==========

[commit-bot: I haz the power, 2017-01-18 20:09:40]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/bc1dbcfdf6fa0db6e78c6ac3af02...