Seems like there are a number of approaches we could try here.
1. Try turning on MSAA and measuring the perf impact.
2. Taking an approach like cc where we expand our quad in screen space by 1/2 pixel and feather the edges.
3. Create quads that will contain the antialiased pixel at the edge (doing fancy math to ensure that they're the right size in screen space).

Please send this back to me if you're not working on this, Tibor.

Issue 767974 has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9f6b20914b84010601dd5c72c2d7882627d29d3d

commit 9f6b20914b84010601dd5c72c2d7882627d29d3d
Author: Ian Vollick <vollick@chromium.org>
Date: Mon Oct 02 22:09:40 2017

[vr] Enable 2x MSAA

This increases the number of samples used in the primary framebuffer.

Bug:  752085 
Change-Id: I869ae41943db925aff845b3d1da15e8130b14e45
Reviewed-on: https://chromium-review.googlesource.com/680374
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505811}
[modify] https://crrev.com/9f6b20914b84010601dd5c72c2d7882627d29d3d/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/9f6b20914b84010601dd5c72c2d7882627d29d3d/chrome/browser/android/vr_shell/vr_shell_gl.h
[modify] https://crrev.com/9f6b20914b84010601dd5c72c2d7882627d29d3d/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/9f6b20914b84010601dd5c72c2d7882627d29d3d/chrome/browser/vr/vr_shell_renderer.cc
[modify] https://crrev.com/9f6b20914b84010601dd5c72c2d7882627d29d3d/chrome/browser/vr/vr_shell_renderer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b6b4aa4c9ce79b177baa20d4be61da06506dfc05

commit b6b4aa4c9ce79b177baa20d4be61da06506dfc05
Author: Ian Vollick <vollick@chromium.org>
Date: Thu Oct 05 19:01:07 2017

Revert "[vr] Enable 2x MSAA"

This reverts commit 9f6b20914b84010601dd5c72c2d7882627d29d3d.

Reason for revert: The timing of the swap_chain_ destruction appears to be wrong. Reverting this until I can sort it out.

Original change's description:
> [vr] Enable 2x MSAA
> 
> This increases the number of samples used in the primary framebuffer.
> 
> Bug:  752085 
> Change-Id: I869ae41943db925aff845b3d1da15e8130b14e45
> Reviewed-on: https://chromium-review.googlesource.com/680374
> Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
> Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> Commit-Queue: Ian Vollick <vollick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#505811}

TBR=vollick@chromium.org,mthiesse@chromium.org,tiborg@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  752085 ,  771663 
Change-Id: I6150abf5840fa81cc9ce135c0746d3fd4f8bca7a
Reviewed-on: https://chromium-review.googlesource.com/702517
Commit-Queue: Ian Vollick <vollick@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506807}
[modify] https://crrev.com/b6b4aa4c9ce79b177baa20d4be61da06506dfc05/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/b6b4aa4c9ce79b177baa20d4be61da06506dfc05/chrome/browser/android/vr_shell/vr_shell_gl.h
[modify] https://crrev.com/b6b4aa4c9ce79b177baa20d4be61da06506dfc05/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/b6b4aa4c9ce79b177baa20d4be61da06506dfc05/chrome/browser/vr/vr_shell_renderer.cc
[modify] https://crrev.com/b6b4aa4c9ce79b177baa20d4be61da06506dfc05/chrome/browser/vr/vr_shell_renderer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/932f55f3dc7976d3aa03680ddbfcc917682ad654

commit 932f55f3dc7976d3aa03680ddbfcc917682ad654
Author: Ian Vollick <vollick@chromium.org>
Date: Wed Oct 11 20:51:47 2017

[vr] Enable 2x MSAA

This increases the number of samples used in the primary framebuffer.

To prevent changing the number of samples on the swap chain buffers
while an acquired frame is in flight (which is illegal), I have
changed VrShellGl to hang onto a ptr to the in-flight frame so we
can check that it is nullptr when we update our MSAA state.

Bug:  752085 
Change-Id: Ibd6d2ca1ddc61b6ecb7e292163c66b5fd2ef400b
Reviewed-on: https://chromium-review.googlesource.com/713234
Commit-Queue: Ian Vollick <vollick@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508105}
[modify] https://crrev.com/932f55f3dc7976d3aa03680ddbfcc917682ad654/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/932f55f3dc7976d3aa03680ddbfcc917682ad654/chrome/browser/android/vr_shell/vr_shell_gl.h
[modify] https://crrev.com/932f55f3dc7976d3aa03680ddbfcc917682ad654/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/932f55f3dc7976d3aa03680ddbfcc917682ad654/chrome/browser/vr/vr_shell_renderer.cc
[modify] https://crrev.com/932f55f3dc7976d3aa03680ddbfcc917682ad654/chrome/browser/vr/vr_shell_renderer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9098789cf7e16b563d3fb7062a709ae3dae0d3c5

commit 9098789cf7e16b563d3fb7062a709ae3dae0d3c5
Author: Brian Sheedy <bsheedy@chromium.org>
Date: Thu Oct 12 18:16:55 2017

Revert "[vr] Enable 2x MSAA"

This reverts commit 932f55f3dc7976d3aa03680ddbfcc917682ad654.

Reason for revert: Causing intermittent crashing on N VR tests.

Original change's description:
> [vr] Enable 2x MSAA
> 
> This increases the number of samples used in the primary framebuffer.
> 
> To prevent changing the number of samples on the swap chain buffers
> while an acquired frame is in flight (which is illegal), I have
> changed VrShellGl to hang onto a ptr to the in-flight frame so we
> can check that it is nullptr when we update our MSAA state.
> 
> Bug:  752085 
> Change-Id: Ibd6d2ca1ddc61b6ecb7e292163c66b5fd2ef400b
> Reviewed-on: https://chromium-review.googlesource.com/713234
> Commit-Queue: Ian Vollick <vollick@chromium.org>
> Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#508105}

TBR=vollick@chromium.org,mthiesse@chromium.org

Change-Id: I45969e1521c51c54205849a0f8741b27cd857596
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  752085 
Reviewed-on: https://chromium-review.googlesource.com/717016
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508373}
[modify] https://crrev.com/9098789cf7e16b563d3fb7062a709ae3dae0d3c5/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/9098789cf7e16b563d3fb7062a709ae3dae0d3c5/chrome/browser/android/vr_shell/vr_shell_gl.h
[modify] https://crrev.com/9098789cf7e16b563d3fb7062a709ae3dae0d3c5/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/9098789cf7e16b563d3fb7062a709ae3dae0d3c5/chrome/browser/vr/vr_shell_renderer.cc
[modify] https://crrev.com/9098789cf7e16b563d3fb7062a709ae3dae0d3c5/chrome/browser/vr/vr_shell_renderer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e832f94b662bc57ed7c7c08823a2089dd4188c01

commit e832f94b662bc57ed7c7c08823a2089dd4188c01
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Fri Oct 20 19:43:26 2017

VR: Fix race in asynchronous drawFrame switching between WebVR and browsing.

When switching between WebVR and browsing, if WebVR is slow it was
possible to have DrawFrame called before DrawFrameSubmitWhenReady
finished for WebVR, leading to issues like resizing buffers causing
crashes.

This CL makes calls to DrawFrame cancel existing callbacks for
DrawFrameSubmitWhenReady, and re-uses the frame for browser rendering.

Bug:  752085 
Change-Id: I087ecc116bcc790bb499f4982fc31d5532374c88
Reviewed-on: https://chromium-review.googlesource.com/721577
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510524}
[modify] https://crrev.com/e832f94b662bc57ed7c7c08823a2089dd4188c01/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/e832f94b662bc57ed7c7c08823a2089dd4188c01/chrome/browser/android/vr_shell/vr_shell_gl.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7

commit 8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7
Author: Ian Vollick <vollick@chromium.org>
Date: Sat Oct 21 16:09:28 2017

[vr] Enable 2x MSAA

This increases the number of samples used in the primary framebuffer.

Bug:  752085 
Change-Id: I55fab0b350bb085c026720c085262ef67e11760d
Reviewed-on: https://chromium-review.googlesource.com/717817
Commit-Queue: Ian Vollick <vollick@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510685}
[modify] https://crrev.com/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7/chrome/browser/android/vr_shell/vr_shell_gl.h
[modify] https://crrev.com/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7/chrome/browser/vr/vr_shell_renderer.cc
[modify] https://crrev.com/8b56bcc2ea30d2bb22f9ab2d4767273fd31863f7/chrome/browser/vr/vr_shell_renderer.h