For comparison: here's safari:

Deleted: safari-boxshadow.mov.gif 70.7 KB

	safari-boxshadow.mov.gif 70.7 KB View Download

Here's a more generic reproduction demo:

https://codepen.io/anon/pen/pObJjO

Hover over the div. 

Some observations:

This happens ONLY when border-radius is > 0px.

Thanks for filing the issue!

Able to reproduce the issue on reported chrome version 70.0.3534.0 using Mac 10.13.1
Note: Issue is not seen on Ubuntu 14.04 and Windows 10

Bisect Information:
-------------------
Good Build: 70.0.3531.0
Bad Build:  70.0.3532.0

Providing the Change log from Omahaproxy as we are getting perf errors while running per-revision and chromium bisect scripts.
https://chromium.googlesource.com/chromium/src/+log/70.0.3531.0..70.0.3532.0?pretty=fuller&n=10000

As we are not very sure about the suspect, tentatively marking it as Untriaged and requesting someone to help us in assigning it to the right owner.
Note: Adding component "Blink>Forms>Button", please change if this isn't apt.

TEs, please do per-revision bisect.

Bisects to this:

https://chromium.googlesource.com/chromium/src/+log/9c9316dc0d0f285c1309ee1e66a1a1913ea61eff..764626c3e8e21e6e2cfe600ffe45cb355dc4c84c

The only likely candidate is a Skia roll:

https://chromium.googlesource.com/chromium/src/+/159d78c6ad47048b9320255e136057afca3e4143

This is almost certainly the problem, because the rendering is correct the first time then wrong subsequently:
2018-08-23 robertphillips@google.com Add GPU-side caching of mask-filtered path masks (take 2)

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/de47928988138babdf2997095f2332ec021f9805

commit de47928988138babdf2997095f2332ec021f9805
Author: Robert Phillips <robertphillips@google.com>
Date: Tue Aug 28 16:30:17 2018

Add a flag to disable mask-filtered mask caching for Chrome

This close to branching, I'm inclined to disable this for M70.

Here is the Chrome-side CL that sets the flag:

https://chromium-review.googlesource.com/c/chromium/src/+/1193968 (
Disable mask-filtered mask caching in Skia)

Bug:  878195 
Change-Id: Ifaf92fac80b75431badb52e0e5b09ccc57c08d8e
Reviewed-on: https://skia-review.googlesource.com/150080
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

[modify] https://crrev.com/de47928988138babdf2997095f2332ec021f9805/src/gpu/GrBlurUtils.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/85101b85e59487cac0675c4c761fda9d9c8d5210

commit 85101b85e59487cac0675c4c761fda9d9c8d5210
Author: Robert Phillips <robertphillips@google.com>
Date: Tue Aug 28 16:52:05 2018

Disable mask-filtered mask caching in Skia

Chrome-side companion to the Skia CL:

https://skia-review.googlesource.com/c/skia/+/150080 (Add a flag to disable mask-filtered mask caching for Chrome)

Bug:  878195 
Change-Id: I8f2f7f2c5fb6dc5a9091750361722bd022e38a45
Reviewed-on: https://chromium-review.googlesource.com/1193968
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Cr-Commit-Position: refs/heads/master@{#586745}
[modify] https://crrev.com/85101b85e59487cac0675c4c761fda9d9c8d5210/skia/config/SkUserConfig.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bd5cd5e696681e4c194fbaa76c3d46609987e92e

commit bd5cd5e696681e4c194fbaa76c3d46609987e92e
Author: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Tue Aug 28 19:58:19 2018

Roll src/third_party/skia 6b622963a065..7ba1d64f0706 (12 commits)

https://skia.googlesource.com/skia.git/+log/6b622963a065..7ba1d64f0706


git log 6b622963a065..7ba1d64f0706 --date=short --no-merges --format='%ad %ae %s'
2018-08-28 brianosman@google.com Revert "Remove old ICC parser, A2B SkColorSpace, SkGammas, etc..."
2018-08-28 brianosman@google.com Fix alpha type when doing GPU color space conversion of unpremul images
2018-08-28 reed@google.com don't support virtual onDrawTextOnPath
2018-08-28 robertphillips@google.com Add a flag to disable mask-filtered mask caching for Chrome
2018-08-28 caryclark@skia.org deprecate draw text on path in docs
2018-08-28 stani@google.com Add support for hardware buffers with protected content
2018-08-28 caryclark@skia.org fix empty region iter rect
2018-08-28 kjlubick@google.com Add docker-based infrastructure for Gold/lottie-web integration
2018-08-28 bsalomon@google.com Make missing resource message print the full expected path
2018-08-28 brianosman@google.com Re-enable 6653 test on IntelVulkan, and label failures better
2018-08-28 robertphillips@google.com More liberally fold the path matrix into the CTM in GrTextBlob::flush
2018-08-28 brianosman@google.com Remove old ICC parser, A2B SkColorSpace, SkGammas, etc...


Created with:
  gclient setdep -r src/third_party/skia@7ba1d64f0706

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel

BUG= chromium:878195 
TBR=stephana@chromium.org

Change-Id: I993e9af1f03b5ca2f62b22dec9f6ce48ec0143ab
Reviewed-on: https://chromium-review.googlesource.com/1194269
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#586822}
[modify] https://crrev.com/bd5cd5e696681e4c194fbaa76c3d46609987e92e/DEPS

 Issue 878617  has been merged into this issue.

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/0b7ce069f2bb4cf73f171bf2aca1dff4e4b8a7b1

commit 0b7ce069f2bb4cf73f171bf2aca1dff4e4b8a7b1
Author: Robert Phillips <robertphillips@google.com>
Date: Wed Aug 29 17:27:50 2018

Always force GPU generated masks be top left

Bug:  878195 
Change-Id: Ie5e89753c2251ee1b4bd60ac2b02cedb7f5292f7
Reviewed-on: https://skia-review.googlesource.com/150133
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

[modify] https://crrev.com/0b7ce069f2bb4cf73f171bf2aca1dff4e4b8a7b1/src/gpu/GrBlurUtils.cpp
[modify] https://crrev.com/0b7ce069f2bb4cf73f171bf2aca1dff4e4b8a7b1/src/core/SkGpuBlurUtils.cpp

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/1b714becff8be9a956d2446ed8abefa0b47c690a

commit 1b714becff8be9a956d2446ed8abefa0b47c690a
Author: Robert Phillips <robertphillips@google.com>
Date: Wed Aug 29 20:02:49 2018

Revert "Always force GPU generated masks be top left"

This reverts commit 0b7ce069f2bb4cf73f171bf2aca1dff4e4b8a7b1.

Reason for revert: Nexus 7 is failing

Original change's description:
> Always force GPU generated masks be top left
> 
> Bug:  878195 
> Change-Id: Ie5e89753c2251ee1b4bd60ac2b02cedb7f5292f7
> Reviewed-on: https://skia-review.googlesource.com/150133
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Robert Phillips <robertphillips@google.com>

TBR=bsalomon@google.com,robertphillips@google.com

Change-Id: I985c9c7fbfa4ca8c09ba7f716d57b9763a589619
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  878195 
Reviewed-on: https://skia-review.googlesource.com/150366
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

[modify] https://crrev.com/1b714becff8be9a956d2446ed8abefa0b47c690a/src/gpu/GrBlurUtils.cpp
[modify] https://crrev.com/1b714becff8be9a956d2446ed8abefa0b47c690a/src/core/SkGpuBlurUtils.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ca1cca8e3afc5fdb10466c839330b9a73feeafb5

commit ca1cca8e3afc5fdb10466c839330b9a73feeafb5
Author: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Wed Aug 29 22:41:21 2018

Roll src/third_party/skia a81c2be75adc..eb0bb732f43f (26 commits)

https://skia.googlesource.com/skia.git/+log/a81c2be75adc..eb0bb732f43f


git log a81c2be75adc..eb0bb732f43f --date=short --no-merges --format='%ad %ae %s'
2018-08-29 herb@google.com Revert "Check that mask to path fallback happens"
2018-08-29 mtklein@google.com Revert "Use skcms_PrimariesToXYZD50 to implement SkColorSpacePrimaries::toXYZD50"
2018-08-29 robertphillips@google.com Revert "Always force GPU generated masks be top left"
2018-08-29 herb@google.com Managing the context was dropped. Adding back in.
2018-08-29 brianosman@google.com Use skcms_PrimariesToXYZD50 to implement SkColorSpacePrimaries::toXYZD50
2018-08-29 bsalomon@google.com Fix GrGLGpu::createTestingOnlyBackendRenderTarget()
2018-08-29 herb@google.com Check that mask to path fallback happens
2018-08-29 kjlubick@google.com [LottieWeb] Fix frames
2018-08-29 mtklein@google.com fix two 1-bit mismatches in sRGB transfer functions
2018-08-29 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader 94d4660dd3f1..60f8662dc0ef (3 commits)
2018-08-29 robertphillips@google.com Always force GPU generated masks be top left
2018-08-29 herb@google.com Add an empty typeface for testing
2018-08-29 allanmac@google.com Update HotSort cl/vk.
2018-08-29 benjaminwagner@google.com [infra] Update Win Radeon drivers.
2018-08-29 benjaminwagner@google.com Update NVIDIA_Shield to Oreo.
2018-08-29 reed@google.com clean up for removing drawTextOnPath from canvas
2018-08-29 csmartdalton@google.com Add a tolerance to SkRemoteGlyphCache_DrawTextAsPath
2018-08-29 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms da25e1a6d412..6b324dbdf772 (1 commits)
2018-08-29 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms 5f03dc9abfb1..da25e1a6d412 (1 commits)
2018-08-29 bsalomon@google.com Temporarily make SkTMultiMap::remove() safe for values not in map
2018-08-29 kjlubick@google.com Correct LottieWeb drawing params
2018-08-29 reed@google.com textonpath no longer in canvas
2018-08-29 michaelludwig@google.com Add setXi and setXiv in GrGLSLProgramDataManager.
2018-08-29 kjlubick@google.com [PathKit] Make pathops assertion a little more forgiving
2018-08-29 brianosman@google.com Remove unused onCanLazyGenerateOnGPU function
2018-08-29 reed@google.com Revert "fix g3 by adding legacy flag"


Created with:
  gclient setdep -r src/third_party/skia@eb0bb732f43f

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel

BUG= chromium:876767 , chromium:878195 ,chromium:877611, chromium:876767 , chromium:878195 ,chromium:877915
TBR=stephana@chromium.org

Change-Id: I312b4a2f488d247a3d7d4bf79453855767290c47
Reviewed-on: https://chromium-review.googlesource.com/1195867
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#587342}
[modify] https://crrev.com/ca1cca8e3afc5fdb10466c839330b9a73feeafb5/DEPS

I have verified that the problem has been suppressed in the 70.0.3537.0 Canary.

[Auto-generated comment by a script] We noticed that this issue is targeted for M-70; it appears the fix may have landed after branch point, meaning a merge might be required. Please confirm if a merge is required here - if so add Merge-Request-70 label, otherwise remove Merge-TBD label. Thanks.

The feature suppression is already in both Skia and Chrome and neither has branched yet. So, no cherry-pick is required for M70. Additionally this feature was not in M69 so there is no need to cherry-pick backwards either.

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/59b39e718fb4a795946d17dca805705c69b6c214

commit 59b39e718fb4a795946d17dca805705c69b6c214
Author: Robert Phillips <robertphillips@google.com>
Date: Thu Aug 30 17:41:10 2018

Always force GPU generated masks be top left (take 2)

Bug:  878195 
Change-Id: Ie5d890597926f160743188ff1011f33e078f3d8f
Reviewed-on: https://skia-review.googlesource.com/150466
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

[modify] https://crrev.com/59b39e718fb4a795946d17dca805705c69b6c214/src/gpu/GrBlurUtils.cpp
[modify] https://crrev.com/59b39e718fb4a795946d17dca805705c69b6c214/src/core/SkGpuBlurUtils.cpp

 Issue 878824  has been merged into this issue.

 Issue 879416  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f406bd5cb2a02810305c8d7b67b3cc85ad7c5a55

commit f406bd5cb2a02810305c8d7b67b3cc85ad7c5a55
Author: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Fri Aug 31 19:00:11 2018

Roll src/third_party/skia 7ed0eae0cd13..9951cbf4ca79 (58 commits)

https://skia.googlesource.com/skia.git/+log/7ed0eae0cd13..9951cbf4ca79


git log 7ed0eae0cd13..9951cbf4ca79 --date=short --no-merges --format='%ad %ae %s'
2018-08-31 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms a6687f8b4d51..80e0493eab5f (1 commits)
2018-08-31 mtklein@google.com update CPU feature macros in src/opts
2018-08-31 khushalsagar@chromium.org fonts: Cap the max number of entries in server side glyph cache tracking
2018-08-31 brianosman@google.com Add support for gray + colorspace to SkCodec
2018-08-31 herb@google.com Extract SkGlyphRunListPainter from SkGlyphRun.*
2018-08-31 mtklein@google.com Reland "standardize macro checks in SkRasterPipeline_opts"
2018-08-31 ethannicholas@google.com fixed uninitialized memory use in arithmetic effect
2018-08-31 bsalomon@google.com Make GrSemaphore a GrGpuResource
2018-08-31 mtklein@google.com Revert "standardize macro checks in SkRasterPipeline_opts"
2018-08-31 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms 018002b16a8a..a6687f8b4d51 (1 commits)
2018-08-31 michaelludwig@google.com Refactor 'in uniform' CPP code generation
2018-08-31 fmalita@chromium.org [skottie] SkTArray begone
2018-08-31 benjaminwagner@google.com Move gbr-gl config from GTX1070 to QuadroP400.
2018-08-31 kjlubick@google.com [PathKit] Remove experimental- from package names
2018-08-31 mtklein@google.com update SkPreConfig a little
2018-08-31 mtklein@google.com standardize macro checks in SkRasterPipeline_opts
2018-08-31 csmartdalton@google.com Revert "ccpr: Implement stroking with fine triangle strips"
2018-08-31 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-31 kjlubick@google.com [PathKit] Move from experimental to modules
2018-08-31 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-31 egdaniel@google.com Add support for switching family queues in vulkan.
2018-08-31 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms b116880ba8e8..018002b16a8a (1 commits)
2018-08-31 mtklein@google.com Revert "update SkPaint size sanity check"
2018-08-31 csmartdalton@google.com ccpr: Implement stroking with fine triangle strips
2018-08-31 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms 5ac66b04c9e3..b116880ba8e8 (1 commits)
2018-08-31 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-31 robertphillips@google.com Fix Fuchsia roll
2018-08-31 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-31 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/angle2 1bf963b62929..fd1621076a74 (1 commits)
2018-08-31 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader 62cfbb9c7876..5fb5e817a20d (1 commits)
2018-08-30 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader 4bbff9eb88c1..62cfbb9c7876 (2 commits)
2018-08-30 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/angle2 44b2c0b1d349..1bf963b62929 (1 commits)
2018-08-30 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-30 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-30 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms 6b324dbdf772..5ac66b04c9e3 (1 commits)
2018-08-30 mtklein@google.com Another manual ANGLE roll
2018-08-30 bungeman@google.com Detect when a FreeType glyph doesn't have a path.
2018-08-30 michaelludwig@google.com Support input color argument to process() function in sksl .fp files
2018-08-30 michaelludwig@google.com Remove GrTextureStripAtlas, textured gradients use independent textures
2018-08-30 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader 60f8662dc0ef..4bbff9eb88c1 (1 commits)
2018-08-30 herb@google.com Remove drawPosText from SkDevice
2018-08-30 herb@google.com Reland "Check that mask to path fallback happens"
2018-08-30 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/angle2 ddc41208c15f..e1037e9be377 (5 commits)
2018-08-30 michaelludwig@google.com Improve inputColor handling in fragment processor implementations.
2018-08-30 herb@google.com Remove drawPosText from svg
2018-08-30 herb@google.com Remove drawPosText_asPath - more dead code
2018-08-30 kjlubick@google.com [Skottie] Fallback to portable font manager
2018-08-30 hcm@google.com Update Skia milestone to 71
2018-08-30 bsalomon@google.com Some GrSemaphore cleanup
2018-08-30 robertphillips@google.com Suppress addition of changeListeners during DDL recording
2018-08-30 herb@google.com Remove drawPosText support for SkBitmapDevice
2018-08-30 ethannicholas@google.com converted arithmetic FP to new FP structure
2018-08-30 robertphillips@google.com Always force GPU generated masks be top left (take 2)
2018-08-30 caryclark@skia.org remove scaling from pathops
2018-08-30 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-30 egdaniel@google.com Fix vulkan validation layer ordering.
2018-08-30 mtklein@google.com roll ANGLE w/ GN update
2018-08-30 kjlubick@google.com Add FuzzPathop to oss-fuzz


Created with:
  gclient setdep -r src/third_party/skia@9951cbf4ca79

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel

BUG=chromium:878966, chromium:876767 , chromium:878195 
TBR=stephana@chromium.org

Change-Id: I27daf0f7bd593680846006414e16f44b47182f8d
Reviewed-on: https://chromium-review.googlesource.com/1199688
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#588104}
[modify] https://crrev.com/f406bd5cb2a02810305c8d7b67b3cc85ad7c5a55/DEPS

Verified the fix on Mac 10.13.1 using Chrome version #71.0.3541.0 as per the comment #0.
Attaching screen cast for reference.
Observed the box shadows rendered properly.
Hence, the fix is working as expected. 
Adding the verified labels.
Note: Able to reproduce the issue on chrome version with out fix.

Thanks...!!

Deleted: 878195 CL Verification.mp4 306 KB

	878195 CL Verification.mp4 306 KB View Download

 Issue 878985  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a2014453d14ec35d485140438224d26d6c1c9d94

commit a2014453d14ec35d485140438224d26d6c1c9d94
Author: Robert Phillips <robertphillips@google.com>
Date: Tue Sep 04 19:40:07 2018

Re-enable caching of mask-filtered masks in Chrome

This was disabled for the M70 branch in:

https://skia-review.googlesource.com/c/skia/+/150080 (Add a flag to disable mask-filtered mask caching for Chrome)
https://chromium-review.googlesource.com/c/chromium/src/+/1193968 (Disable mask-filtered mask caching in Skia)

However, the fix for the causal bug was landed in Skia in:

https://skia-review.googlesource.com/c/skia/+/150466 (Always force GPU generated masks be top left (take 2))

So this feature should be safe to re-enable

Bug:  878195 
Change-Id: I56b13987ed3755f399bfc82c2bd580004d139d08
Reviewed-on: https://chromium-review.googlesource.com/1204651
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Cr-Commit-Position: refs/heads/master@{#588619}
[modify] https://crrev.com/a2014453d14ec35d485140438224d26d6c1c9d94/skia/config/SkUserConfig.h

 Issue 881940  has been merged into this issue.

When moving the cursor in to the Gmail Compose button, I'm Able to see the issue on Chrome 72.0.3602.0/11232.0.0 - Daisy.

Deleted: Screenshot 2018-11-07 at 8.12.55 AM.png 13.6 KB

	Screenshot 2018-11-07 at 8.12.55 AM.png 13.6 KB View Download

Unable to reproduce the issue on 72.0.3602.0/11232.0.0 - Kefka device.

songsuk@ are you able to see this in M70?

Unable to reproduce the issue on Chrome 70.0.3538.76/11021.56.0 - Daisy

Able to reproduce the issue on 71.03578.39/11151.23.0 - daisy, banjo

This seems to be old bug, does this repro live Beta for Mac?

Response to C#33, No issue seen on Mac using chrome beta-71.0.3578.44 as mentioned in C#0. Observed box shadow rendered properly on Mac beta.

Please find the attached screencast for reference.
Thanks.!

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	878195-beta-no issue on Mac.mp4 1.4 MB View Download

Removing the OS-Mac label as this is not reproducible on latest M71 Beta # 71.0.3578.44 & M72 ToT build # 72.0.3608.4 - Mac OSX 10.13.6 [Macbook Air]

Removing ReleaseBlock label as this is not a new regression. It was found in M70 (M70 is already in stable).

This is seen on CrOS Device Panther - 11151.38.0 / 71.0.3578.61

Deleted: Compose Button on Panther M71.JPG 6.4 MB

	Compose Button on Panther M71.JPG 6.4 MB View Download

Probably related: Box Shadows are also broken for an older version of the Bootstrap CSS framework using latest stable Chrome 71.x on MacOS.

Please see the bootstrap docs: https://getbootstrap.com/2.3.2/base-css.html#forms

Then scroll to "Optional Layouts" -> "Search forms" and focus the search input field.

The `box-shadow: 0 0 8px ...` is not "centered" but instead appears to the top-left of the input field. The behavior however is flaky, sometimes it works sometimes not. If it doesn't work for you try to force focus state via Chrome devtools on the element.

Another issue I've noticed on the same element: There's some flickering attached to the box-shadow transition.

Both issues are kinda new. I don't know the exact Chrome version which introduced these issues but I guess it must have been Chrome 71 or 70.

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The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/55ff5d3ba88117c667214fc6b4e08768eddc11b2

commit 55ff5d3ba88117c667214fc6b4e08768eddc11b2
Author: Robert Phillips <robertphillips@google.com>
Date: Tue Jan 08 13:05:30 2019

Fix truncation of sigma parameter in blur-mask-filtered mask key

This would allow blur-masks alias one another.

Bug: 912595
Bug:  878195 
Change-Id: I44e86e893a505cf8abd991975a025cda52011db6
Reviewed-on: https://skia-review.googlesource.com/c/181902
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

[modify] https://crrev.com/55ff5d3ba88117c667214fc6b4e08768eddc11b2/src/gpu/GrBlurUtils.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f4077a406ff0dfc2c9dca34de00e0ef12d1342a7

commit f4077a406ff0dfc2c9dca34de00e0ef12d1342a7
Author: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Date: Tue Jan 08 16:01:02 2019

Roll src/third_party/skia bf515da22a7f..55ff5d3ba881 (14 commits)

https://skia.googlesource.com/skia.git/+log/bf515da22a7f..55ff5d3ba881


git log bf515da22a7f..55ff5d3ba881 --date=short --no-merges --format='%ad %ae %s'
2019-01-08 robertphillips@google.com Fix truncation of sigma parameter in blur-mask-filtered mask key
2019-01-08 robertphillips@google.com Revert "Make SkBitmap/SkPixmap::erase* do so in sRGB"
2019-01-08 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset
2019-01-08 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 5df1d281a992..eb278cb04e97 (1 commits)
2019-01-08 mtklein@google.com update p3 GM
2019-01-08 reed@google.com no more text encoding in paint
2019-01-07 brianosman@google.com Revert "Revert "Support combining per-vertex coverage with color in default GP vertex shader""
2019-01-07 skia-autoroll@skia-public.iam.gserviceaccount.com Roll skia/third_party/skcms d2f489e79366..cecf6c0ebb91 (1 commits)
2019-01-07 csmartdalton@google.com Revert "ccpr: Support caching of paths that span multiple tiles"
2019-01-07 scroggo@google.com Make SkBitmap/SkPixmap::erase* do so in sRGB
2019-01-07 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader f6d56f15c09e..24e71928441e (1 commits)
2019-01-07 csmartdalton@google.com ccpr: Support caching of paths that span multiple tiles
2019-01-07 caryclark@skia.org fix bookmaker
2019-01-07 jcgregorio@google.com Fix extra semicolon.


Created with:
  gclient setdep -r src/third_party/skia@55ff5d3ba881

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux-blink-rel;luci.chromium.try:linux-chromeos-compile-dbg;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel

BUG=chromium:912595, chromium:878195 
TBR=bsalomon@chromium.org

Change-Id: I05f5183fcaf4ac2c17b828211d43569aff9a11f4
Reviewed-on: https://chromium-review.googlesource.com/c/1400612
Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#620741}
[modify] https://crrev.com/f4077a406ff0dfc2c9dca34de00e0ef12d1342a7/DEPS

Responding to #40 and #41, the CL that landed in #42 & #43 fixed a mask aliasing issue that could plausibly manifest as the behavior you described. Could you see if the problems are fixed with that change?

The change is a one line change in Skia's GrBlurUtils.cpp file so it should be easy to test locally regardless of the Chromium branch you are using.

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/d7ae3da7f2879de968a56570a1585b78d643cc6f

commit d7ae3da7f2879de968a56570a1585b78d643cc6f
Author: Robert Phillips <robertphillips@google.com>
Date: Wed Jan 09 20:50:51 2019

[M72 cherry-pick] Fix truncation of sigma parameter in blur-mask-filtered mask key

This would allow blur-masks alias one another.

No-Tree-Checks: true
No-Try: true
No-Presubmit: true
Bug: 912595
Bug:  878195 
Change-Id: I44e86e893a505cf8abd991975a025cda52011db6
Reviewed-on: https://skia-review.googlesource.com/c/182665
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Robert Phillips <robertphillips@google.com>

[modify] https://crrev.com/d7ae3da7f2879de968a56570a1585b78d643cc6f/src/gpu/GrBlurUtils.cpp

Responding to #44, I tested it locally on Chromium with your changes. The problem is fixed, thanks.
Also, here is a demo of this issue, just in case: https://codepen.io/astronautr/details/jXdpQO.

#46 - great! - thanks for the update. I'm marking this as fixed until I hear different.

Note that the fix was only cherry picked backed to M72 so it will still appear in M71.