Just came to file this, so it's great to see it's already on the radar.

We're hitting this in Polymer because our development server is using UA-sniffing to decide whether to compile JavaScript, and device emulation is triggering the wrong decision there (compounded by the fact that Chrome has native Custom Elements and say, iPhone 6 doesn't).

It would be really great if device emulation UA strings had some clue that it's Chrome so that something like our devserver could check that it's really Chrome. I understand that this might cause an arms race of cloaking, but lying causes problems too.

Also, I's suggest that the UA string for Safari be for 10.1, since both Chrome and Safari 1.0 have native ShadowDOM and Custom Elements.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9f8d4632b417d2f4fa8216f9be3a19a16554806c

commit 9f8d4632b417d2f4fa8216f9be3a19a16554806c
Author: Erik Luo <luoe@chromium.org>
Date: Fri Dec 15 02:07:37 2017

DevTools: update user agents and add Pixel 2 device presets

Bumps user agents for iOS and Nexus devices, and adds Pixel 2 and its
XL presets.

Retired from show-by-default:
iPhone 7, iPhone 7 Plus, Nexus 6P, Galaxy S5

Added to show-by-default:
iPhone 5, Pixel 2, Pixel 2 XL

Bug:  707877 
Change-Id: I1801427ebc622fca46d23fc6e57bfbb6152680d5
Reviewed-on: https://chromium-review.googlesource.com/826247
Commit-Queue: Erik Luo <luoe@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524289}
[modify] https://crrev.com/9f8d4632b417d2f4fa8216f9be3a19a16554806c/third_party/WebKit/Source/devtools/front_end/emulated_devices/module.json