The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2d72b38b601cb38a10384e8d32045ec8b0042845

commit 2d72b38b601cb38a10384e8d32045ec8b0042845
Author: Sadrul Habib Chowdhury <sadrul@chromium.org>
Date: Mon Jan 08 05:57:13 2018

oopif events: Scale the location only when appropriate.

Some platforms use zooming to implement device-scale-factor (e.g. on
linux, windows). It is necessary to convert the hit-test point from DIP
to physical-pixel space only on those platforms. In other platforms
(e.g. on mac, android), it is not necessary to apply the device-scale
factor before hit-testing in blink.

BUG= 797661 , 793018

Change-Id: If5252d598f29c007d967d3c35eddac049abfc989
Reviewed-on: https://chromium-review.googlesource.com/853161
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527577}
[modify] https://crrev.com/2d72b38b601cb38a10384e8d32045ec8b0042845/content/browser/site_per_process_browsertest.cc
[modify] https://crrev.com/2d72b38b601cb38a10384e8d32045ec8b0042845/content/renderer/input/render_widget_input_handler.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b

commit bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b
Author: Sadrul Habib Chowdhury <sadrul@chromium.org>
Date: Mon Jan 08 14:46:38 2018

oopif events: Fix a couple of issues with async event targeting.

. The renderer already applies the device-scale-factor during hit-test.
  So avoid doing any scaling on the browser side.
. When querying a nested client for targeting, make sure the location
  is correctly transformed to that view's coordinate space.

BUG= 797661 , 793018

Change-Id: I65d74ad49fb25d1a9cb05745e2a2f8d3ac26763e
Reviewed-on: https://chromium-review.googlesource.com/848033
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527632}
[modify] https://crrev.com/bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b/content/browser/renderer_host/render_widget_targeter.cc
[modify] https://crrev.com/bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b/content/browser/site_per_process_browsertest.cc
[add] https://crrev.com/bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b/content/test/data/frame_tree/page_with_content_overlap_positioned_frame.html
[modify] https://crrev.com/bc55716b7ce8d4a19eea2b4b9d62bf4ad72e7a6b/testing/buildbot/filters/viz.content_browsertests.filter