Here are screenshots for patchset 1 of crrev.com/c/875131

Deleted: overflowmenu.subtitles.patch1.noicons.png 29.0 KB

	overflowmenu.subtitles.patch1.noicons.png 29.0 KB View Download

Deleted: overflowmenu.subtitles.patch1.withicons.png 33.1 KB

	overflowmenu.subtitles.patch1.withicons.png 33.1 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/675ea8a902e3fa23e85897210a715a2eef9b87f5

commit 675ea8a902e3fa23e85897210a715a2eef9b87f5
Author: Tommy Steimel <steimel@chromium.org>
Date: Mon Jan 22 16:41:38 2018

Add ability for Media Controls to show a subtitle in the overflow menu

This CL adds a virtual String GetOverflowMenuSubtitleString method to
MediaControlInputElement that subclasses can override to provide text
to show beneath the element's overflow menu item text.

This only shows up in the modern Media Controls. This CL does not add
any subtitles yet, just adds the ability to add them.

Bug:  775539 
Change-Id: I5075f9881b1d86f8562b72b94b86976c436e15fd
Reviewed-on: https://chromium-review.googlesource.com/875131
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530880}
[modify] https://crrev.com/675ea8a902e3fa23e85897210a715a2eef9b87f5/third_party/WebKit/Source/modules/media_controls/elements/MediaControlInputElement.cpp
[modify] https://crrev.com/675ea8a902e3fa23e85897210a715a2eef9b87f5/third_party/WebKit/Source/modules/media_controls/elements/MediaControlInputElement.h
[modify] https://crrev.com/675ea8a902e3fa23e85897210a715a2eef9b87f5/third_party/WebKit/Source/modules/media_controls/resources/modernMediaControls.css

Here is a screencast for patchset 1 of crrev.com/c/881583

Deleted: crbug.775539.captions.webm 603 KB

	crbug.775539.captions.webm 603 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f

commit 6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f
Author: Tommy Steimel <steimel@chromium.org>
Date: Wed Jan 24 19:57:52 2018

Add subtitle to captions overflow button

This CL adds a subtitle to the MediaControls captions overflow button
that displays the name of the selected text track, or "Off" if no text
track is selected. The logic for determining the name of the track is
reused from MediaControlTextTrackListElement, and has been moved to
MediaControlsImpl to be shared.

Bug:  775539 
Change-Id: I450e7be2bcd994f3461e388e6ddc5e160617c8c6
Reviewed-on: https://chromium-review.googlesource.com/881583
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#531656}
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/BUILD.gn
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/elements/MediaControlTextTrackListElement.cpp
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/elements/MediaControlTextTrackListElement.h
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/elements/MediaControlToggleClosedCaptionsButtonElement.cpp
[modify] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/elements/MediaControlToggleClosedCaptionsButtonElement.h
[add] https://crrev.com/6d87e2dd0ee6ace84d1f1a135b0aca5e2d9e835f/third_party/WebKit/Source/modules/media_controls/elements/MediaControlToggleClosedCaptionsButtonElementTest.cpp

What's remaining here?

Failed to CC myself *facefalm*.

The cast button is also supposed to have a subtitle

subtitle icon available through MD icons https://icons.googleplex.com/#search=subtitle

Thanks for the link Amy, I've pasted it on  bug 353120  (which is the one about the icon). This was about the text regarding the name of the language/cast device. Will mark as fix and open another one for the cast device as the blocking factor here is that we do not know the cast device name in Blink.