That sounds like a bug indeed. Will see what I can do.

Leaving some notes of what I found: the thumb is painted in MediaControlsPainter, making it ignore things like disabled state. The usual way of making a control "disabled" wouldn't work well because the thumb is blue and it would make it blue and slightly transparent which makes the bar below the thumb visible.

We need to find how to paint the thumb grey and transparent instead of blue and transparent.

Hello Mlamouri, 

 Please find the patch uploaded here:https://codereview.chromium.org/2982573002/

Cheers,

Hello Mlamouri, 

  Please find the new patch uploaded here : https://chromium-review.googlesource.com/c/chromium/src/+/857474

Apologies I have been away for some time now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8409a370efd2e617f9738e592bdbe7907e0671c8

commit 8409a370efd2e617f9738e592bdbe7907e0671c8
Author: George Joseph <kottackal.george@gmail.com>
Date: Tue Jan 16 18:04:03 2018

Grey slider thumb when preload is disabled.

A video tag should not highlight the play button
and slider thumb when preload is disabled and
no source is present

BUG= 665149 

Change-Id: Icd6a44b28609d9a11ef2719b0d421c0b4a2a58e4
Reviewed-on: https://chromium-review.googlesource.com/857474
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529460}
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.txt
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber.html
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.txt
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/LayoutTests/platform/win7/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/Source/modules/media_controls/resources/default_100_percent/legacy/mediaplayer_slider_thumb_grey.png
[modify] https://crrev.com/8409a370efd2e617f9738e592bdbe7907e0671c8/third_party/WebKit/Source/modules/media_controls/resources/legacyMediaControls.css

Thanks George! :)

Thanks a lot Mounir. Happy to help.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a98df58d846735bfc7f05fbfb3b03fb32bce1f6a

commit a98df58d846735bfc7f05fbfb3b03fb32bce1f6a
Author: Jonathan Ross <jonross@chromium.org>
Date: Tue Jan 16 20:20:30 2018

Revert "Grey slider thumb when preload is disabled."

This reverts commit 8409a370efd2e617f9738e592bdbe7907e0671c8.

Reason for revert: The test that this change adds, media/media-controls-grey-scrubber.html has been failing consistently on the WebKit Win 10 bots.

https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Win10/builds/29740


Original change's description:
> Grey slider thumb when preload is disabled.
> 
> A video tag should not highlight the play button
> and slider thumb when preload is disabled and
> no source is present
> 
> BUG= 665149 
> 
> Change-Id: Icd6a44b28609d9a11ef2719b0d421c0b4a2a58e4
> Reviewed-on: https://chromium-review.googlesource.com/857474
> Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
> Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#529460}

TBR=chrishtr@chromium.org,mlamouri@chromium.org,kottackal.george@gmail.com

Change-Id: I09e290557c4bbde7dbbd63746493b8077c975142
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  665149 
Reviewed-on: https://chromium-review.googlesource.com/868496
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529495}
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.png
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.txt
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber.html
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.png
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.txt
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/LayoutTests/platform/win7/media/media-controls-grey-scrubber-expected.png
[delete] https://crrev.com/62157460a07ed38f23d4ee24146205306ca9d1a1/third_party/WebKit/Source/modules/media_controls/resources/default_100_percent/legacy/mediaplayer_slider_thumb_grey.png
[modify] https://crrev.com/a98df58d846735bfc7f05fbfb3b03fb32bce1f6a/third_party/WebKit/Source/modules/media_controls/resources/legacyMediaControls.css

Hello Mounir, 

It looks like the WebKit Win10 bot does not render the layout like the win10_chromium_x64_rel_ng. Any ideas if an expectation can be added for the WebKit Win 10?

Thanks, 
George.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dead4b5a97458337c3f9cd1c7dd3665d05861656

commit dead4b5a97458337c3f9cd1c7dd3665d05861656
Author: George Joseph <kottackal.george@gmail.com>
Date: Thu Mar 08 09:40:48 2018

Grey slider thumb when preload is disabled.

A video tag should not highlight the play button
and slider thumb when preload is disabled and
no source is present

BUG= 665149 

Change-Id: I2ee71d95f7c1cf289c2e7892b30845c77bc1bd1f
Reviewed-on: https://chromium-review.googlesource.com/905643
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541760}
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber-expected.txt
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/media/media-controls-grey-scrubber.html
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/platform/linux/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.png
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/LayoutTests/platform/mac/media/media-controls-grey-scrubber-expected.txt
[add] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/Source/modules/media_controls/resources/default_100_percent/legacy/mediaplayer_slider_thumb_grey.png
[modify] https://crrev.com/dead4b5a97458337c3f9cd1c7dd3665d05861656/third_party/WebKit/Source/modules/media_controls/resources/legacyMediaControls.css