Chrome Version: 54.0.2816.0 (Official Build) 5ca3397bac11535fb30249c96b9ee311fe2474a8-refs/heads/master@{#409090} (32/64-bit)
OS: Windows (8,10)

URL: https://chrome.google.com/webstore/detail/google-hangouts/nckgahadagoaajjgafhacjanaoiihapd?utm_source=chrome-app-launcher-info-dialog

Steps:
1. Launch Chrome, add above extension and click on Hangout extension icon beside ominibox.
2. Hover mouse on Collapse/Close icon seen on overlay, then move mouse after tooltip is seen and observe

Actual: Unwanted traces are seen on hangout extension window after tool-tip disappears

Expected: No such traces should be seen on hangout extension window after tool-tip disappears.

This is a regression issue broken in M-54, below is bisect info.

Good build: 54.0.2803.0
Bad build: 54.0.2805.0

Narrow bisect:
https://chromium.googlesource.com/chromium/src/+log/ef206ad2f2bd182205b4adb5580c00e7967c4fd8..149a3740a58de22cd0ebbd0fe962a9f116c2e776?pretty=fuller&n=10000

Suspecting: r407268?

Please help to re-assign if your change is not the cause for this issue.

Note: 1. This is Windows(8,10) OS specific issue not seen on Mac, Linux and Windows 7 OS
      2. Unable to capture traces in screenshot or screen cast.