Version: 57.0.2980.0 6770bab14919fc9abed1d457387824e84cc43602-refs/heads/master@{#443474} (64-bit)
OS: Windows(7,8,8.1,10),Linux (14.04 LTS),Mac OS X(10.11.6, 10.12.1)

What steps will reproduce the problem?
1. Launch chrome and navigate to chrome://md-settings/ and click on 'Main Menu' button to open side navigation panel
2. Now continuously press 'Shift' and 'Tab' key from keyboard to traverse the focus in reverse direction and observe the blue focus highlight on side navigation panel.

Actual: Unnecessary blue focus highlight is seen on entire side navigation panel options which is not working
Expected: Unnecessary blue focus highlight should not be seen in side navigation panel

This is regression issue, broken in ‘M 50’ and below is manual regression and narrow bisect info:
Good build : 50.0.2641.0 
Bad build : 50.0.2643.0 

Narrow Bisect info : 
https://chromium.googlesource.com/chromium/src/+log/37d34f19f114e53b2876df543dc67b6061da8c78..f6f66ac71683543ade0945ce9d8951f7b546ec7e?pretty=fuller&n=100

Suspecting: r373893 from Narrow bisect

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

 

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