Chrome Version : 68.0.3424.0 (Official Build) 7b31b2ed3f03336596e6193a8e93fd961bd06c03-refs/branch-heads/3424@{#1} 32/64-bit
OS : Windows(7,8,8.1,10), Mac(10.12.6, 10.13.1, 10.13.5), Linux(14.04 LTS)

What steps will reproduce the problem?
1. Launch chrome and navigate to chrome://downloads page.
2. Open devtools and click on 'Toggle device toolbar' button. (Page enters into device mode)
3. Now double click anywhere on the downloads page and observe.

Actual Result : Unable to zoom in downloads page using double click when page is in emulated mode. 

Expected Result : chrome://downloads page should get zoom in/out on double clicking, in emulated mode.

This is a regression issue, broken in M-66 and providing the bisect using per-revision script:
Good Build : 66.0.3352.0 (Revision : 538314)
Bad Build : 66.0.3353.0 (Revision : 538677)

You are probably looking for a change made after 538571 (known good), but no later than 538572 (first known bad).

Change Log URL :
https://chromium.googlesource.com/chromium/src/+log/3398bc96d2085f09837f011891f7e1cfcb81e425..be690ef47f6ab92d2f11785f569014bd77386743

Suspect : https://chromium.googlesource.com/chromium/src/+/be690ef47f6ab92d2f11785f569014bd77386743

@dpapad : 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.

Note : 
1. Issue is also observed in Stable build #66.0.3359.139, Dev #68.0.3418.2 and Beta #67.0.3396.30
 

Deleted: Actual_Result.mp4 400 KB

	Actual_Result.mp4 400 KB View Download

Deleted: Expected_Result.mp4 430 KB

	Expected_Result.mp4 430 KB View Download