Version: 55.0.2883.18 fef9e129659e95716a20748335f5921e324bab8a-refs/branch-heads/2883@{#164} (64-bit)
OS: Windows (7,8,8.1,10),Linux (14.04 LTS),Mac OS X(10.10.5, 10.11.4)

What steps will reproduce the problem?
1. Launch chrome and navigate to NTP and open devtools.
2. Now go to 'Sources' section and click on 'Watch' at bottom.
3. Now resize 'Watch' window to RHS and observe

Actual: Scroll bar doesn't appear after dragging 'Watch' window to RHS
Expected: Scroll bar should appear after dragging 'Watch' window to RHS

This is regression issue, broken in ‘M 42’ and below is manual regression and narrow bisect info:
Good build : 42.0.2309.2
Bad build : 42.0.2311.4

Narrow Bisect info : 
https://chromium.googlesource.com/chromium/src/+log/76ec1ea76ba6116e1e8a07706f43dd80009d209f..66af5887986c6e397eb502be312a98dc6e7d6d9b?pretty=fuller&n=100

Blink Change Log :
https://chromium.googlesource.com/chromium/blink/+log/de34936..8ca446a?pretty=fuller&n=100

Suspecting: 190480 from Blink CL

@sergeyv : Could you please help to reassign if your change is not the cause for this change.

 

Deleted: Actual_video.mov 1.2 MB

Actual_video.mov 1.2 MB Download

Deleted: Expected_video.mov 909 KB

Expected_video.mov 909 KB Download

Deleted: Actual_screenshot.png 1.1 MB

	Actual_screenshot.png 1.1 MB View Download

Deleted: Expected_screenshot.png 1.0 MB

	Expected_screenshot.png 1.0 MB View Download