All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=613172

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjKiTpgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgzLDIpQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjM_tuQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjK_KvQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjK_eogoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjPmXsAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjNuwoQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjNussAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjIXVrQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjMX2ugoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgzLDrsgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjK_3uwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgjK-FswkM


Bot(s) for this bug's original alert(s):

android-galaxy-s5
android-nexus5X
android-nexus6
android-nexus7v2
chromium-rel-mac-hdd
chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-single
chromium-rel-win7-x64-dual
chromium-rel-win8-dual
linux-release

The range is https://chromium.googlesource.com/chromium/src/+log/0537a6d11bf2ebefcf90fbfec7081e37ef78081a%5E..2768accc154d067704fb501967de68cba9fa4c3b?pretty=fuller

The most likely culprit seems to be: 
crrev.com/393827 - bindings: Supports [SameObject] extended attribute.

yukishiino@ can you please take a look.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4

commit fdd68c2f872ba56475500d80dcf02b1aeb97cbc4
Author: yukishiino <yukishiino@chromium.org>
Date: Fri May 20 13:34:11 2016

Revert of bindings: Supports [SameObject] extended attribute. (patchset #2 id:20001 of https://codereview.chromium.org/1980553002/ )

Reason for revert:
This CL hits terrible performance regressions.

Original issue's description:
> bindings: Supports [SameObject] extended attribute.
>
> Syntactically we've supported [SameObject] extended attribute,
> but we've not had any implementation for it.
>
> This CL stores the first returned value in the holder's
> private value, and returns it for the second time.
>
> BUG= 462913 
>
> Committed: https://crrev.com/40d19a73c02f0185e5a49c4761860762896dec28
> Cr-Commit-Position: refs/heads/master@{#393827}

TBR=bashi@chromium.org,haraken@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG= 462913 ,  613172 ,  613170 

Review-Url: https://codereview.chromium.org/2000643002
Cr-Commit-Position: refs/heads/master@{#395064}

[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/LayoutTests/fast/dom/gc-9-expected.txt
[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/Source/bindings/scripts/v8_attributes.py
[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/Source/bindings/templates/attributes.cpp
[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/Source/bindings/tests/results/core/V8TestObject.cpp
[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/Source/core/css/CSSImportRule.cpp
[modify] https://crrev.com/fdd68c2f872ba56475500d80dcf02b1aeb97cbc4/third_party/WebKit/Source/core/css/CSSImportRule.idl

It turned out that https://crrev.com/2000643002 was committed in M53, but not in M52, and M52 still has the performance regression.

Let me request a merge of the CL to M52.

I'm very sorry that I haven't noticed it and I haven't merged the CL much earlier.

[Automated comment] Request affecting a post-stable build (M52), manual review required.

M52 is already in Stable for Desktop and bar is VERY high. We're going to have M52 refresh Stable release next week and we can take this change in ONLY if it is critical, well baked/verified in Canary/dev/beta and  very safe to merge. Please confirm this. Thank you.

Also is this change applicable to all OS or any specific OS?

haraken@, majidvp@ and I discussed briefly.  This was only detected by a single benchmark, and this is unlikely to impact real world sites right now (though it may have a more pronounced affect on libraries such as Polymer).

Given that M52 is already rolling out to stable and that all new changes pose risk, we decided it is best not to revert.  Thus merge rejected and marking back as fixed.

Please take care to merge fixes back to release branches sooner in the future (though thank you for noticing and attempting to follow up when you did notice).