Do we know if we have any device in 180~200 range? Or we're ok to change it even if it exists?

Based on my conversation with sgabriel@, yes we are ok changing it. (sgabriel@ please correct me if I misunderstood)

FWIW I'm pretty sure there's no such device, but even if there is we're ok making this change.

+mark, greg as the display folks so they're aware of this change

We need to co-ordinate these changes with changing the hardware requirements.

Should we discuss if at the same time we need to add 2.25x for >=275dpi or >=280dpi? On the display trip last year we started to see all vendors offer displays in the 280-325 ppi range. (275 is where the touch target falls below 9mm at 2x, but could change the high res version of HP chell which has been shipping a while, so we may want to do the jump at 280)

Jumping to 280 doesn't seem problematic to me, especially if a device already ships in 2x for the >=275 range.

We should also make sure we get proper ARC scaling for 280, I believe current bucket for Android places the threshold at 320 but I remember discussing making it 275 on CrOS (280 now then). It's what currently specced in the spectrum: https://gallery.googleplex.com/projects/MCHbtQVoQ2HCZZMqpNeZZG0f/files/MCF6Z_OZIEnbufFWMhQTTr5AwMSJbxAVNpw

ARC++ uses 0.75 x chrome scale, so it'll be  1.69 for 2.25 device.

In case there is misunderstanding, the android's threshold is used to select the resources (mdpi, hdpi, xhdpi etc), and actual dpi can be in between.

ah got it, thanks Oshima I always need to be reminded how it works :)
In this case we'd still get resources from xhdpi right ? Seems like hdpi scaled up might result in bad rendering.

Yes, dpi that Android sees will be 270, which is in xhdpi range (240~320]

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ddf2ded45aba2a9522000bfa6c6daac2c4347ab2

commit ddf2ded45aba2a9522000bfa6c6daac2c4347ab2
Author: F#m <malaykeshav@chromium.org>
Date: Thu Jan 18 19:15:31 2018

Update DPI range for 1.6x scale from 200-220 to 180-220

This patch updates the range of DPI that sets a device scale factor
of 1.6 for displays from 200-220 to 180-220.

Bug:  800580 
Change-Id: I23cd5f37980180d83e4bad1df997258accdb3ba6
Component: Display Change Observer, Device scale factor
Reviewed-on: https://chromium-review.googlesource.com/865540
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Malay Keshav <malaykeshav@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530224}
[modify] https://crrev.com/ddf2ded45aba2a9522000bfa6c6daac2c4347ab2/ui/display/manager/chromeos/display_change_observer.cc
[modify] https://crrev.com/ddf2ded45aba2a9522000bfa6c6daac2c4347ab2/ui/display/manager/chromeos/display_change_observer_unittest.cc

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/requirements/+/0ade7f9da2865d42e9a8b12b5890fa589552ab13

commit 0ade7f9da2865d42e9a8b12b5890fa589552ab13
Author: Mark Hayter <mdhayter@mdhayter840.mtv.corp.google.com>
Date: Tue Jan 23 18:58:53 2018