onbeforeprint seems similarly broken. This bisects to https://chromium.googlesource.com/chromium/src/+log/2555486f..623c4e77 so it is very likely due to r597054.

Based on comment#2 this is a M71 regression hence tagging the bug as Stable blocker.

In general, onbeforeprint and onafterprint events are used for making web pages into a print-friendly layout (e.g. removing unnecessary banners, ads, etc.), and I'm afraid that these events would have major impacts on businesses (form print, receipt print, etc.).

I think that it's better to merge a fix into M71.

I've prepared a fix at:
https://chromium-review.googlesource.com/c/chromium/src/+/1368848

The fix is simple and pretty safe to merge.  I confirmed the fix with local build.

this is exactly my case, I have a business line application this bug caused a big problem in the impressions.

I would be very happy to release an update soon.

Can i get some more context regarding the issue, why it's an emergency, and why it's a stable blocker?  And why it was discovered so late in testing?  Timing is pretty bad for release plans

Re #5, Thank you yukishiino@. Could you pls merge the change to current canary branch 3633 once it lands so I can trigger new canary from same branch to make sure we get canary coverage? 

Is this bug applicable to Android as well?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fa8fd965900a1ae66630aa9b36f1e837178f32e7

commit fa8fd965900a1ae66630aa9b36f1e837178f32e7
Author: Yuki Shiino <yukishiino@chromium.org>
Date: Sat Dec 08 16:24:39 2018

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614972}
[modify] https://crrev.com/fa8fd965900a1ae66630aa9b36f1e837178f32e7/third_party/blink/renderer/bindings/core/v8/js_event_handler.cc
[modify] https://crrev.com/fa8fd965900a1ae66630aa9b36f1e837178f32e7/third_party/blink/renderer/bindings/core/v8/js_event_listener.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dad0533b9a6bfda7b09b0bac2850b99ffea62fec

commit dad0533b9a6bfda7b09b0bac2850b99ffea62fec
Author: Yuki Shiino <yukishiino@chromium.org>
Date: Sat Dec 08 16:36:27 2018

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614972}(cherry picked from commit fa8fd965900a1ae66630aa9b36f1e837178f32e7)
Reviewed-on: https://chromium-review.googlesource.com/c/1369209
Reviewed-by: Krishna Govind <govind@chromium.org>
Cr-Commit-Position: refs/branch-heads/3634@{#3}
Cr-Branched-From: 87ffab8656b43fd2a6b49c0bc62dc97bc26ebde5-refs/heads/master@{#614909}
[modify] https://crrev.com/dad0533b9a6bfda7b09b0bac2850b99ffea62fec/third_party/blink/renderer/bindings/core/v8/js_event_handler.cc
[modify] https://crrev.com/dad0533b9a6bfda7b09b0bac2850b99ffea62fec/third_party/blink/renderer/bindings/core/v8/js_event_listener.cc

I've merged the change listed at #9 to current canary branch 3634 and triggering new canary from same branch - https://chromium.googlesource.com/chromium/src.git/+/dad0533b9a6bfda7b09b0bac2850b99ffea62fec.

Re #c7: The issue is that 'onbeforeprint' and 'onafterprint' event dispatching doesn't work at all.  These events are usually used to make web pages into print-friendly layout so that printed papers do not include side menu, banners, redundant headers/footers, ads, etc.

I'm afraid that those who are doing "print web pages from Chrome" will be affected by the issue.  For example, application forms, receipts, etc. will be printed in unpleasant format/layout.  Those who're printing from Chrome in their daily business will be affected.  I personally think that it's worth stable blocking.


Re #c8: All platforms other than iOS are affected, including Android and Chrome OS, not limited to desktop.  I guess that it's not so rare nowadays to print web pages from Chrome on Android and Chrome OS.  I imagine that some merchants use Android tablets for their business and print web pages.

Re #c10: And thanks for the merge to Canary.

Adding OS=Android per comment #12 (+benmason@ Chrome on Android TPM).

Canary 73.0.3634.2 is currently building with this merge for Android, Desktop and CrOS.

Canary #73.0.3634.2 went live which includes this merge. Pls update bug with canary result on Monday morning PT.

Thanks for the quick merge!

I believe that the fix is trivial and is a very low risk. i.e., it would be safe to merge to stable.

Thank you haraken@.

Approving merge to M71 branch 3578 based on comments #5, #12 and #16. 
Pls merge to M71 only after verifying on canary if change looks good. Thank you.

This will also need a merge to M72, so approving merge to M72 branch 3626.

Confirmed the fix on Canary on Mac: Version 73.0.3635.0 (Official Build) canary (64-bit)

(beforeprint, afterprint) x (event handler, event listener), all combinations work as expected.  I'll merge the fix to M71 and M72 tomorrow (Monday in JST).

Re #19: Sounds good, Thank you.

Any chance this can get merged to M71 asap so I'll have a version of chrome with the fix on Monday for Chrome OS?  Thanks

I'm trying to merge to M71 to unblock Stable RC cut for Chrome OS.

Sorry, I try to merge to M71 branch 3578 but unable to merge due to merge conflict. Getting below error:

An error occurred
Could not perform action: Cherry pick failed: merge conflict.


 yukishiino@, pls resolve merge conflict and then merge to M71. Thank you.

Pls merge you change to M72 branch 3626 ASAP so we can pick it up for next  Dev/Beta release, RC cut on Monday, 12/10 @ 1:00 PM PT. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d6e7d74e2f4b33b0797dfc2183f6d345538971d9

commit d6e7d74e2f4b33b0797dfc2183f6d345538971d9
Author: Yuki Shiino <yukishiino@chromium.org>
Date: Mon Dec 10 06:38:10 2018

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614972}(cherry picked from commit fa8fd965900a1ae66630aa9b36f1e837178f32e7)
Reviewed-on: https://chromium-review.googlesource.com/c/1369555
Cr-Commit-Position: refs/branch-heads/3626@{#172}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
[modify] https://crrev.com/d6e7d74e2f4b33b0797dfc2183f6d345538971d9/third_party/blink/renderer/bindings/core/v8/js_event_handler.cc
[modify] https://crrev.com/d6e7d74e2f4b33b0797dfc2183f6d345538971d9/third_party/blink/renderer/bindings/core/v8/js_event_listener.cc

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/4cf3d0904c332b3676790c7dc532bbaee5aea8e9

Commit: 4cf3d0904c332b3676790c7dc532bbaee5aea8e9
Author: yukishiino@chromium.org
Commiter: yukishiino@chromium.org
Date: 2018-12-10 07:59:37 +0000 UTC

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

(cherry picked from commit fa8fd965900a1ae66630aa9b36f1e837178f32e7)

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614972}
Reviewed-on: https://chromium-review.googlesource.com/c/1369561
Cr-Commit-Position: refs/branch-heads/3578@{#886}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4cf3d0904c332b3676790c7dc532bbaee5aea8e9

commit 4cf3d0904c332b3676790c7dc532bbaee5aea8e9
Author: Yuki Shiino <yukishiino@chromium.org>
Date: Mon Dec 10 07:59:37 2018

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

(cherry picked from commit fa8fd965900a1ae66630aa9b36f1e837178f32e7)

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614972}
Reviewed-on: https://chromium-review.googlesource.com/c/1369561
Cr-Commit-Position: refs/branch-heads/3578@{#886}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
[modify] https://crrev.com/4cf3d0904c332b3676790c7dc532bbaee5aea8e9/third_party/blink/renderer/bindings/core/v8/js_event_handler.cc
[modify] https://crrev.com/4cf3d0904c332b3676790c7dc532bbaee5aea8e9/third_party/blink/renderer/bindings/core/v8/js_event_listener.cc

Thank you yukishiino@.

Triggered new M71 build with this merge in for Android, Desktop and Chrome OS - version 71.0.3578.93 (currently building).

Able to reproduce this issue on Windows 10, Mac OS 10.13.6 and Ubuntu 17.10 on the reported version 71.0.3578.80 and the issue is fixed on the latest M-73 build 73.0.3636.0.

1. Launched Chrome and entered window.onafterprint = function(){console.log('after')}; and window.print(); in Devtools -> Console.
2. Could observe that 'after' is printed in the console.
Attached is the screen shot for reference.

Hence adding TE verified labels as the fix is working as intended.

Thanks..

Deleted: 912966-M73.PNG 49.8 KB

	912966-M73.PNG 49.8 KB View Download

The NextAction date has arrived: 2018-12-10

re #c28: M71 desktop builds finished.  The build results of 71.0.3578.93 are the same as ones of 71.0.3578.92 (previous one).  Some of content_browsertests and browser_tests are failing in the same way.  So, no difference between 93 and 92.

Chrome for Android is still in the middle of building.

re #c28: M71 Android builds finished successfully with all green.

I'll try to write a test for this, to make it harder to regress.

Able to reproduce this issue on Windows 10, Mac OS 10.13.6 and Ubuntu 17.10 on the reported version 71.0.3578.80 and the issue is fixed on the latest M-72 build 72.0.3626.14.

1. Launched Chrome and entered window.onafterprint = function(){console.log('after')}; and window.print(); in Devtools -> Console.
2. Could observe that 'after' is printed in the console.
Attached is the screen shot for reference.

Hence adding TE verified labels as the fix is working as intended.

Thanks..

//attaching screen shot for comment #35

Deleted: 912966-M72.PNG 49.4 KB

	912966-M72.PNG 49.4 KB View Download

Tested the issue on Windows 10, Mac OS 10.13.6, Ubuntu 17.10 and the issue is fixed on the latest M-71 build 71.0.3578.95.
Hence adding TE verified labels.

Thanks..

 Issue 914019  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/39e5d59018f0fb802cff93a5d9793c0905b9b497

commit 39e5d59018f0fb802cff93a5d9793c0905b9b497
Author: Lei Zhang <thestig@chromium.org>
Date: Tue Dec 11 19:31:22 2018

Add more PrintRenderFrameHelperTests.

- PrintRenderFrameHelperTest.WindowPrintBeforePrintAfterPrint covers the
  regression in  bug 912966  without Print Preview.
- PrintRenderFrameHelperPreviewTest.WindowPrintBeforePrintAfterPrint
  covers the regression in  bug 912966  with Print Preview.
- PrintRenderFrameHelperPreviewTest.BasicBeforePrintAfterPrint is the
  equivalent to PrintRenderFrameHelperTest.BasicBeforePrintAfterPrint,
  but for Print Preview.
- Merge common code to avoid repeats.

BUG= 912966 

Change-Id: I80b0ef718e4f06e2e1bd858bd1c2a39028d4a6ec
Reviewed-on: https://chromium-review.googlesource.com/c/1371211
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615624}
[modify] https://crrev.com/39e5d59018f0fb802cff93a5d9793c0905b9b497/components/printing/test/print_render_frame_helper_browsertest.cc

 Issue 914018  has been merged into this issue.

Good news: 71.0.3578.98 is now available with the fix on Chrome Stable. You can force an update by visiting chrome://chrome. Thank you.

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/d6e7d74e2f4b33b0797dfc2183f6d345538971d9

Commit: d6e7d74e2f4b33b0797dfc2183f6d345538971d9
Author: yukishiino@chromium.org
Commiter: yukishiino@chromium.org
Date: 2018-12-10 06:38:10 +0000 UTC

v8binding: Invoke on{before,after}print event listeners even when paused

This patch fixes a regression at https://crrev.com/c/1215512 ,
which doesn't run '{before,after}print' event listeners when one
of the related execution contexts is paused.  This is almost the
same fix as https://crrev.com/c/1333548 .

Another idea for fix is that Blink should pause an execution
context in a narrower range; after dispatching onbeforeprint event
and before dispatching onafterprint event.  However, the content/
layer has the control of printing and event dispatching, and it's
not easy to change such an overall design in a short term.
See also WebLocalFrame::Dispatch{Before,After}PrintEvent and its
implementations and call sites:
https://cs.chromium.org/chromium/src/third_party/blink/public/web/web_local_frame.h?rcl=92c06acc4c92805f4020ad1b12c537fa4ac122c3&l=670

With such a background, this patch allows exceptional invocations
not only for beforeunload event but also {before,after}print event.

TBR=haraken@chromium.org

Bug:  912966 
Change-Id: Id38be3ea61668a8e88274b95a4192837e469bd48
Reviewed-on: https://chromium-review.googlesource.com/c/1368848
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614972}(cherry picked from commit fa8fd965900a1ae66630aa9b36f1e837178f32e7)
Reviewed-on: https://chromium-review.googlesource.com/c/1369555
Cr-Commit-Position: refs/branch-heads/3626@{#172}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}