https://chromium-review.googlesource.com/c/chromium/src/+/720019 maybe?

Missing the equivalent change for webview in https://chromium-review.googlesource.com/c/chromium/src/+/720019/22/content/browser/renderer_host/compositor_impl_android.cc ?

Yea, looks like WebView always reports a DSF of 1.0 to Viz:

https://cs.chromium.org/chromium/src/android_webview/browser/surfaces_instance.cc?type=cs&q=surfaces_instance.cc&sq=package:chromium&l=153

How do I plumb the view's device scale factor for Webview?

Note to self:

https://cs.chromium.org/chromium/src/android_webview/browser/hardware_renderer.cc?type=cs&q=AddChildId+file:%5Esrc/android_webview/browser/+package:%5Echromium$&l=164

It looks like surfaces_->DrawAndSwap likely should just get the device scale factor of the child CompositorFrame which should be getting the right device scale factor from the browser ultimately through WebContentsViewAndroid...I think. I'll try to fix this tomorrow. Thanks!

 Issue 785708  has been merged into this issue.

fsamuel@, do you think this can be fixed by today? If not, I think we need to revert your changes.

fix is in cq: https://chromium-review.googlesource.com/776078

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/64d7ccec1afeaa0c4d11d1db5b74770440398ccf

commit 64d7ccec1afeaa0c4d11d1db5b74770440398ccf
Author: Fady Samuel <fsamuel@chromium.org>
Date: Fri Nov 17 02:27:41 2017

Surface synchronization: Report correct DSF to Viz in android_webview

SurfacesInstance's CompositorFrame always reported a device scale factor
of 1. When surface scaling was moved to SurfaceAggregator, viz started
scaling surfaces relative to their parent. The renderer's CompositorFrame
correctly reported a DSF of 2. However, as the top level CF reported
a DSF of 1, SurfaceAggregator scaled the renderer down. This CL fixes
the problem by making surface the top level CompositorFrame reports
the right device scale factor.

Bug:  785596 ,  672962 
Change-Id: Ife0668ae3f7c531265119d2b37954918504444ae
Reviewed-on: https://chromium-review.googlesource.com/776078
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517253}
[modify] https://crrev.com/64d7ccec1afeaa0c4d11d1db5b74770440398ccf/android_webview/browser/hardware_renderer.cc
[modify] https://crrev.com/64d7ccec1afeaa0c4d11d1db5b74770440398ccf/android_webview/browser/surfaces_instance.cc
[modify] https://crrev.com/64d7ccec1afeaa0c4d11d1db5b74770440398ccf/android_webview/browser/surfaces_instance.h

This should be fixed now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/267a787d9029e32d37359eb67905f6e327bb97f2

commit 267a787d9029e32d37359eb67905f6e327bb97f2
Author: Fady Samuel <fsamuel@chromium.org>
Date: Fri Nov 17 19:57:58 2017

Surface synchronization: Report correct DSF to Viz in android_webview

SurfacesInstance's CompositorFrame always reported a device scale factor
of 1. When surface scaling was moved to SurfaceAggregator, viz started
scaling surfaces relative to their parent. The renderer's CompositorFrame
correctly reported a DSF of 2. However, as the top level CF reported
a DSF of 1, SurfaceAggregator scaled the renderer down. This CL fixes
the problem by making surface the top level CompositorFrame reports
the right device scale factor.

TBR=fsamuel@chromium.org

(cherry picked from commit 64d7ccec1afeaa0c4d11d1db5b74770440398ccf)

Bug:  785596 ,  672962 
Change-Id: Ife0668ae3f7c531265119d2b37954918504444ae
Reviewed-on: https://chromium-review.googlesource.com/776078
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#517253}
Reviewed-on: https://chromium-review.googlesource.com/777679
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/branch-heads/3271@{#3}
Cr-Branched-From: 71f07f2c6c77c9e67158a193516e2f0c6229ce64-refs/heads/master@{#517250}
[modify] https://crrev.com/267a787d9029e32d37359eb67905f6e327bb97f2/android_webview/browser/hardware_renderer.cc
[modify] https://crrev.com/267a787d9029e32d37359eb67905f6e327bb97f2/android_webview/browser/surfaces_instance.cc
[modify] https://crrev.com/267a787d9029e32d37359eb67905f6e327bb97f2/android_webview/browser/surfaces_instance.h

Issue 787013 has been merged into this issue.

battun@ verified this on pixel XL /OPM1.171019.013 with latest webview version M64:64.0.3281.0.

Thanks!