Able to reproduce this on the latest canary(50.0.2627.0) on Windows-7, Mac OS 10.11.2, Linux Ubuntu 14.04.

This is a regression issue broken in M-49.

Last good build: 49.0.2614.0
First bad build: 49.0.2615.0

Change log:
===========
https://chromium.googlesource.com/chromium/src/+log/58c142c6eccd0287edcf0194391f785e45a8de92..a4231e4994a90b513122bdb9a58069d26938849f

hayato@: Could you please confirm if this could be related to https://codereview.chromium.org/1530643003.

Okay. I have tried to reproduce. The result is:

- At the commit: https://crrev.com/b7c3414768afff35204a6c6b869c47d90d3953e0 
  => Video can not be loaded. It says "No valid source could be found"

- Before the commit of b7c3414768afff35204a6c6b869c47d90d3953e0
  => Video can not be loaded. It says "No valid source could be found"

Though these errors look different from the canary's error, the CL, https://codereview.chromium.org/1530643003, looks unrelated to this issue, I guess.

ajaha@, could you find another culprit?  Does the regression happens on this range? 
https://chromium.googlesource.com/chromium/src/+log/58c142c6eccd0287edcf0194391f785e45a8de92..a4231e4994a90b513122bdb9a58069d26938849f

Requesting a re bisect.

Rebisected and got the same bisect as in C#2.
===================================================
Bisecting range [367742 (good), 367969 (bad)].
Trying revision 367816...
Revision 367816 is [(g)ood/(b)ad/(r)etry/(u)nknown/(q)uit]: b
Downloading revision 367785...
Bisecting range [367742 (good), 367816 (bad)].
Trying revision 367785...
Revision 367785 is [(g)ood/(b)ad/(r)etry/(u)nknown/(q)uit]: g
Downloading revision 367798...
Bisecting range [367785 (good), 367816 (bad)].
Trying revision 367798...
Revision 367798 is [(g)ood/(b)ad/(r)etry/(u)nknown/(q)uit]: b
Downloading revision 367792...
Bisecting range [367785 (good), 367798 (bad)].
Trying revision 367792...
Revision 367792 is [(g)ood/(b)ad/(r)etry/(u)nknown/(q)uit]: b
Downloading revision 367788...
Bisecting range [367785 (good), 367792 (bad)].
Trying revision 367788...
Revision 367788 is [(g)ood/(b)ad/(r)etry/(u)nknown/(q)uit]: g
You are probably looking for a change made after 367788 (known good), but no later than 367792 (first known bad).
CHANGELOG URL:
https://chromium.googlesource.com/chromium/src/+log/58c142c6eccd0287edcf0194391f785e45a8de92..a4231e4994a90b513122bdb9a58069d26938849f


There is V8 roll as well, in the above Change log:
======================================================
https://chromium.googlesource.com/v8/v8/+log/5041f175..aca25b0c

Unable to find the exact suspect, hence Cc'ing devs for further investigation of this.

Could anyone of you please take a look and confirm if the changes could be related to this or help in investigating this further.

The link is 404 for me. 

"Something has gone wrong...

It seems you clicked on a bad link and stumbled upon our 404 page" 

Perhaps it has been removed? Is there another page where this reproduces?

Go to www.foxnews.com
Click on any video on the right hand side.
It will reproduce.
Repeat with other browsers - it works.

Thanks.

It's likely a v8 issue. I notice the following console.error that I don't get in chrome:

[32306:32306:0122/100403:3285843977826:INFO:CONSOLE(20360)] "Uncaught SyntaxError: Identifier 'RecommendationsPlugin' has already been declared", source: http://foxnewsplayer-a.akamaihd.net/player/7.38.1.0003/amp.premier/amp.premier.js (20360)

Bisects down to https://chromium.googlesource.com/v8/v8/+/fcff8588a5a01587643d6c2507c7b882c78a2957. littledan@ PTAL.

I stumbled upon another problem when trying to play the movies. Even without the V8 culprit I cannot play the videos (but the player starts correctly) because of:

Uncaught NotSupportedError: Failed to execute 'addSourceBuffer' on 'MediaSource': The type provided ('video/mp4;codecs=mp4a.40.5') is unsupported.

Do we have two distinct issues?

To clarify: I don't think the second issue (addSourceBuffer) is V8 related.

Micheal can we land the fix before 5 PM today. We plan for a dev channel on Monday which will be promoted to Beta on Thursday ( Jan 28).

I'm going to work on narrowing this down this afternoon.

This is the same bug as https://bugs.chromium.org/p/v8/issues/detail?id=4693

In particular, the following function declaration appears twice in the same closure:

function RecommendationsPlugin() {
  RecommendationsPlugin.__super__.constructor.call(this);
}

The second declaration thus triggers a syntax error under the new semantics.

To be a little more specific, the two functions are inside an if-statement inside a closure.

I have a work-in-progress patch that fixes this, though as hablich@ says, I still get a different error about addSourceBuffer. But maybe that's because I'm on Linux?

https://codereview.chromium.org/1622723003/ is now working its way throught the V8 commit queue, will update this thread with a plan of action once it successfully lands.

Everything's green so far, waiting on the Chromium bot. I intend to merge this to the 4.9 branch once it lands, as the window for getting canary coverage before the dev cut seems too short to be a useful signal.

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/8aeb6080e11548c018e898a078a162c23a45f7b8

commit 8aeb6080e11548c018e898a078a162c23a45f7b8
Author: adamk <adamk@chromium.org>
Date: Sat Jan 23 00:40:15 2016

Sloppy mode webcompat: allow conflicting function declarations in blocks

The web appears to depend on being able to redeclare functions-in-blocks
in sloppy mode (examples seen so far tend to redeclare identical functions,
most likely accidentally).

This patch opens a minimal hole: two same-named function declarations
in the same scope are allowed, only in sloppy mode.

BUG= v8:4693 ,  chromium:579395 
LOG=y

Review URL: https://codereview.chromium.org/1622723003

Cr-Commit-Position: refs/heads/master@{#33478}

[modify] http://crrev.com/8aeb6080e11548c018e898a078a162c23a45f7b8/src/parsing/parser.cc
[add] http://crrev.com/8aeb6080e11548c018e898a078a162c23a45f7b8/test/mjsunit/regress/regress-4693.js
[modify] http://crrev.com/8aeb6080e11548c018e898a078a162c23a45f7b8/test/test262/test262.status

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c

commit 5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c
Author: Adam Klein <adamk@chromium.org>
Date: Sat Jan 23 00:44:12 2016

Version 4.9.385.11 (cherry-pick)

Merged 8aeb6080e11548c018e898a078a162c23a45f7b8

Sloppy mode webcompat: allow conflicting function declarations in blocks

BUG= chromium:579395 , v8:4693 
LOG=N
TBR=hablich@chromium.org

Review URL: https://codereview.chromium.org/1621663003 .

Cr-Commit-Position: refs/branch-heads/4.9@{#13}
Cr-Branched-From: 2fea296569597e5064f81fd8fce58f1848de261a-refs/heads/4.9.385@{#1}
Cr-Branched-From: 0c1430ac2b65847559d6a09f883ee7e5a91063c9-refs/heads/master@{#33306}

[modify] http://crrev.com/5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c/include/v8-version.h
[modify] http://crrev.com/5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c/src/parsing/parser.cc
[add] http://crrev.com/5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c/test/mjsunit/regress/regress-4693.js
[modify] http://crrev.com/5e69f90f5de3f5a3f92f3b1e02c33aafe3bda36c/test/test262/test262.status

The V8-related issue has now been fixed, and that fix merged to the branch. But the media format error hablich@ saw in #c11 was still present when I tested this fix on Linux.

Thanks Adam for the quick turnaround.

Requesting Amit to try a bisect to narrow down for media format error.

This is working fine on the latest M-49(49.0.2623.23), JavaScript: V8 4.9.385.11 on Windows-7, Mac OS 10.11.2 and Linux Ubuntu 14.04.

Didn't observe any Media format error under the console while playing the videos on Windows, Mac or Linux. Did see the 'VM763:2 pepflashplayer.dll: 0xC92 is not a valid resource ID.' under console when the video was playing. This has been showing the same since older chrome version: 38.0.2064.0. Chrome version before that doesn't allow the videos to play as the Flash player is not updated.

Attached is the screen-shot of the console when the video is playing on Windows. Could anyone review the attached screenshot.

Thank you! 

	579395_WindowConsole.png 827 KB View Download

I'm going to mark this fixed, as videos now play (per #26). If we want to look into those console warnings, I recommend opening a separate bug with knowledgeable folks attached (they wouldn't be V8 folks).

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/11e8c03f94c6110d9bc7397741a6904580fac86b

commit 11e8c03f94c6110d9bc7397741a6904580fac86b
Author: littledan <littledan@chromium.org>
Date: Mon Feb 01 23:01:13 2016

Add UseCounters for some nonstandard JavaScript features

This patch adds a UseCounter for each of the following:
- Allowing duplicate sloppy-mode block-scoped function declarations
  in the exact same scope
- for-in loops with an initializer

The patch also refactors some of the declaration code to clean it up and
enable the first counter, and adds additional unit tests to nail down
the semantics of edge cases of sloppy-mode block-scoped function declarations.

BUG= v8:4693 , chromium:579395 
LOG=N
R=adamk

Review URL: https://codereview.chromium.org/1633743003

Cr-Commit-Position: refs/heads/master@{#33650}

[modify] http://crrev.com/11e8c03f94c6110d9bc7397741a6904580fac86b/include/v8.h
[modify] http://crrev.com/11e8c03f94c6110d9bc7397741a6904580fac86b/src/parsing/parser.cc
[modify] http://crrev.com/11e8c03f94c6110d9bc7397741a6904580fac86b/test/mjsunit/regress/regress-4693.js