danakj@ Thanks for the issue.

Tested this issue on Windows 10, Mac OS 10.12.6 on the latest Stable 63.0.3239.132 and Canary 65.0.3314.0 and unable to reproduce the issue by following the steps mentioned in original comment.

On Navigating to the given website and loading the site with unsafe scripts, a media player is appearing and music is playing without any issues.
Attached is the screen cast for reference.

Request you to please retry the issue on a new chrome profile without any flags/extensions and update the thread with the observations.

Thanks.. 

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Thanks, you're right. My command line looks like

Command Line	"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --enable-features=top-document-isolation --flag-switches-begin --flag-switches-end

Even though I have put OOPIF back to "default" state in chrome://flags. When I force it off then the page behaves. So this is a bug in top-document-isolation/OOPIF.

Thank you for providing more feedback. Adding requester "sc00335628@techmahindra.com" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Able to reproduce the issue on Windows 10, mac 10.12.6 and Ubuntu 14.04 using chrome reported version #63.0.3239.132 and latest canary #65.0.3315.3.
But unable to provide bisect results as on digging to get the good and bad range, at chrome version #60.0.3112.0 and upper builds till M-62 on performing the 5th and 6th steps from comment #0, again a tiny icon appeared in the omnibox right side to load unsafe scripts and nothing happened. Loaded the unsafe scripts 2-3 times, still it remained the same and media player was not seen.
Attaching screen cast of M-60 for reference 
Hence, marking it as untriaged for further inputs from dev team.

Thanks...!!

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	799770.mp4 3.9 MB View Download

Nasko: Can you triage this in your team? Based on #4 above, it sounds like the mixed content opt-out is broken in some way related to site isolation.

(Lowering this to P3, as we're kinda thinking about removing that mechanism altogether: +estark@ for opinions)

alexmos@: We have another bug about this, right?  Is it issue 496670, or is there something more recent?

Sorry, I was getting content settings and mixed content confused in comment 9.  (Content settings was found to be working as intended in  issue 767539 .)  This is about mixed content instead.

Yes, this is indeed problem with mixed content settings not propagating to out-of-process iframes (OOPIFs). The conclusion about mixed content in issue 496670 comment 3 is not correct. The problem is that after "Load unsafe scripts" is clicked, the main frame reloads and all its child frames are gone. When an iframe is then navigated to a new process, that new process does not get the correct value for allow_running_insecure_content_ inside ContentSettingsObserver.

I'll resolve this one as duplicate of issue 496670 and add more details there with potentially a simplified repro.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/72c8c945f44b515aa30ac9f6a34f46314eb9dd92

commit 72c8c945f44b515aa30ac9f6a34f46314eb9dd92
Author: Nasko Oskov <nasko@chromium.org>
Date: Sat Jan 13 01:01:26 2018

Set correct value for allowing mixed content in out-of-process iframes.

When mixed content is detected, it is blocked by default. The user can
chose to allow it, in which case the browser tells the renderer to
set its value for "allow mixed content" to true. Within a single renderer
process, frames inherit this value from the main frame, but in the face
of out-of-process iframes, this does not work.
This CL adds an observer for new frames being created and if mixed content
is allowed, it sets the proper value on its RenderFrame.

Bug: 496670,  799770 
Change-Id: Ica7e2f4122d54b14b2186e2941f59c93d7738e51
Reviewed-on: https://chromium-review.googlesource.com/862700
Commit-Queue: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529126}
[modify] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/browser/content_settings/mixed_content_settings_tab_helper.cc
[modify] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/browser/content_settings/mixed_content_settings_tab_helper.h
[modify] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/browser/ui/content_settings/content_setting_bubble_model_browsertest.cc
[modify] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/test/data/content_setting_bubble/mixed_script.html
[add] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/test/data/content_setting_bubble/mixed_script.js
[add] https://crrev.com/72c8c945f44b515aa30ac9f6a34f46314eb9dd92/chrome/test/data/content_setting_bubble/mixed_script_in_cross_site_iframe.html