Chrome Version:63.0.3216.0 (Official Build) c3592928ad6753206a00d98787a578cda6153570-refs/heads/master@{#502108}

OS: MAC (Retina 10.12)

Steps to reproduce:
1)Launch chrome ,open devtools on NTP and click o. 
2)Click on 'import bookmarks now' link and observe.

Actual Result:'Import bookmarks now' link is unresponsive on navigating through devtools.
Expected Result: 'Import bookmarks now' link should not get unresponsive on navigating through devtools.

This is regression issue broken in 'M-63' and below per-revision bisect result

Using the per-revision bisect providing the bisect results,
Good build: 63.0.3212.0          
Bad build: 63.0.3213.0


Note:Issue is not seen on Windows(7,8,10), Linux(14.04 LTS) and Mac(10.11.6, 10.12.3, 10.12.5).

You are probably looking for a change made after 501080 (known good), but no later than 501081 (first known bad).

CHANGELOG URL:

The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/158a7a01ceb96fd019e996e3501d2fd2995bebb2..27caae83cb530daaf49f9a38793e427cdf493a65

Suspect:https://chromium.googlesource.com/chromium/src/+/27caae83cb530daaf49f9a38793e427cdf493a65

@Alex Moshchuk : Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

 Thanks.
 

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Actual Result.mov 3.4 MB Download

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Expected Result.mov 1.8 MB Download