Chrome Version: 60.0.3112.30 (Official Build) (cohort: 59_86_Win)3c3a751adc7b297b98a09461f8df5caa1cf52e56-refs/branch-heads/3112@{#304}(32/64-bit).

OS: Windows(7,8,8.1,10).

Steps to reproduce:
1. Launch chrome, go to chrome://extensions, Click on Details link for Google Docs Extension.
2.On Google Docs Extension overlay, click on the drop down.
3.Now, click on details link for another extension and observe.

Actual Result: Unnecessary able to access background page.
Expected Result: should not be able to access background page.

This is Non-regression issue broken in M-43,  and below is the Narrow Bisect Info

Manual Bisect:
Good Build: 43.0.2334.0
Bad Build: 43.0.2335.0 

Note: Issue is not reproducible in MAC and LINUX OS


Narrow Bisect Info:
https://chromium.googlesource.com/chromium/src/+log/b386883d993bba40562b565b98da4ffe72e82b1d..8f2fd17e33f365c1a73dd25aa33a3a2877d0c1d5?pretty=fuller&n=10000

Suspecting: r320805?

@rdevlin.cronin: Kindly help to re-assign if your change is not the cause for this issue.
 

Deleted: Actual Result.mp4 944 KB

	Actual Result.mp4 944 KB View Download

Deleted: Expected Result.mp4 683 KB

	Expected Result.mp4 683 KB View Download