Manual bisect:
Good build: 51.0.2683.0 
Bad build: 51.0.2684.0 

Narrow bisect URL:
https://chromium.googlesource.com/chromium/src/+log/efbc81bcc0145b3df17eaa9bd24c833fad958e83..c273884cebc427b90d7b989c1210ebb0ffeebfe3?pretty=fuller&n=10000

Suspecting: r382145

Note: Issue is not seen on Mac and Linux OS.

Deleted: browser_actual.mp4 690 KB

browser_actual.mp4 690 KB Download

Deleted: browser_expected.mp4 754 KB

browser_expected.mp4 754 KB Download

Marking this as RB-Stable blocker as this need to fixed before M51 goes to stable.

Feel free to remove if someone thinks otherwise.

Thank you!

r382145 is an Android-only change, so if you're seeing this issue on Windows it must be something else.

M51 Stable is launching very soon! Your bug is labelled as Stable ReleaseBlock, pls make sure to land the fix and get it merged ASAP. All changes MUST be merged into the release branch by 5pm on May 20 to make into the desktop Stable final build cut. Thank you!

I have checked the regression range by picking the Build numbers mentioned in Comment#1 and I see the same result last Good build : 51.0.2683.0 and first Bad build : 51.0.2684.0.

Please find the Change log between those two builds :
https://chromium.googlesource.com/chromium/src/+log/51.0.2683.0..51.0.2684.0?pretty=fuller&n=10000

Gentle Ping to get an update on this Stable blocker for M-51.

I have a fix for the hang, but still need to create a unit test. Currently, I've been pulled off on a regression. Should return to this by tomorrow or Monday.

M51 Stable is launching very soon! Your bug is labelled as Stable ReleaseBlock, pls make sure to land the fix and get it merged ASAP. All changes MUST be merged into the release branch by 5pm on May 20 to make into the desktop Stable final build cut. Thank you!

Awaiting a final LGTM for the CL. 

CL is now in the commit queue: https://codereview.chromium.org/1978163003/ for origin/master. 

Thank you kylixrd@. Please request a merge to M51 once CL is laded/baked/verified in Canary. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3972b0ed7c8531f67f7e796fa6f939a70f2694f9

commit 3972b0ed7c8531f67f7e796fa6f939a70f2694f9
Author: kylixrd <kylixrd@chromium.org>
Date: Thu May 19 21:07:42 2016

If the window handle is destroyed because of an owner being destroyed, ensure any disabled windows are enabled.

BUG= 612117 

Review-Url: https://codereview.chromium.org/1978163003
Cr-Commit-Position: refs/heads/master@{#394861}

[modify] https://crrev.com/3972b0ed7c8531f67f7e796fa6f939a70f2694f9/ui/views/widget/widget_unittest.cc
[modify] https://crrev.com/3972b0ed7c8531f67f7e796fa6f939a70f2694f9/ui/views/win/hwnd_message_handler.cc

I couldn't reproduce this on the latest canary(52.0.2743.0) and the reported version(52.0.2738.0) on Windows-7.

However this reproduced on the chrome version(52.0.2741.0 - before the fix) and worked fine on chrome version(52.0.2743.0 -after the fix) on Windows-10.

Adding the verified label and requesting kylixrd@ to get this merged to M-51.

kylixrd@, as per comment #16, this is already verified by TE in canary. Could you please request a merge to M51 by applying "Merge-Request-51" label? We need this to be merged by 12:00 PM PST tomorrow (Tuesday). Thank you.

[Automated comment] Less than a week to go before stable on M51, we might already have a stable candidate build. Manual review required.

Merge approved for M51 (branch 2704)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c568e0abad0165b514ec74b3bbcd02343b739ca9

commit c568e0abad0165b514ec74b3bbcd02343b739ca9
Author: Sadrul Habib Chowdhury <sadrul@chromium.org>
Date: Tue May 24 20:24:45 2016

If the window handle is destroyed because of an owner being destroyed, ensure any disabled windows are enabled.

BUG= 612117 

Review-Url: https://codereview.chromium.org/1978163003
Cr-Commit-Position: refs/heads/master@{#394861}
(cherry picked from commit 3972b0ed7c8531f67f7e796fa6f939a70f2694f9)

Review URL: https://codereview.chromium.org/2008103002 .

Cr-Commit-Position: refs/branch-heads/2704@{#654}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}

[modify] https://crrev.com/c568e0abad0165b514ec74b3bbcd02343b739ca9/ui/views/widget/widget_unittest.cc
[modify] https://crrev.com/c568e0abad0165b514ec74b3bbcd02343b739ca9/ui/views/win/hwnd_message_handler.cc

Tested the same on win8.1 chrome version 51.0.2704.74 and browser did not become unresponsive on selecting 'Ask Google for suggestions' option.

Adding TE-Verified labels.

Marking this as Fixed as this is merged and verified in M-51.