Bug Report: Missing Screen Sharing Infobar on macOS

[AAdonis]

🐞 Bug Report: Missing Screen Sharing Infobar on macOS

Environment:

• NW.js: official release build (nwjs-sdk-v0.106.0： https://dl.nwjs.io/v0.106.0/)
• OS: macOS macOS 15.6.1)
• Hardware: Mac mini (M4)

Steps to Reproduce:

1. Launch the official NW.js binary.
2. Open the demo page: WebRTC getDisplayMedia sample
3. Click Start.
4. In the system dialog, select a window to share.
5. Confirm sharing.

Expected Behavior:

• After sharing starts, macOS should display the screen sharing infobar at the bottom of the screen (with “Stop sharing / Hide”).

Actual Behavior:

• The infobar does not appear.
• Screen sharing works, but the user has no visible system indicator or stop button.

Notes:

• This behavior differs from running the same demo in Chrome on macOS, where the infobar appears correctly.
• It seems NW.js may not be wiring up Chromium’s SharingIndicatorController or related UI components on macOS.
• This is a security/usability issue: users cannot easily stop sharing once started.

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🔎 Possible Root Cause Analysis

It appears that NW.js on macOS is not wiring up Chromium’s built‑in SharingIndicatorController or related UI components when screen capture is initiated. In Chrome, after navigator.mediaDevices.getDisplayMedia() succeeds, Chromium triggers the SharingIndicatorController to display the infobar (“Stop sharing / Hide”).

As a result, screen sharing works, but the user‑visible indicator is suppressed. This differs from Chrome’s behavior and creates a usability/security gap.

The expected screen sharing infobar window at the bottom of the screen is as follows:

[AAdonis]

Hi @ayushmanchhabra

Issue Summary

We identified the root cause of the issue in
chrome/browser/media/webrtc/desktop_capture_devices_util.cc at line 293 , within the implementation of the CreateMediaStreamCaptureIndicatorUI function..

The screen sharing infobar UI was disabled due to the use of #if 0 conditional compilation.
To resolve this, we replaced #if 0 with #if BUILDFLAG(IS_MAC), enabling the infobar UI specifically on macOS.
After applying this change, testing confirmed that the problem was fixed.

Questions for Maintainers

1.Is the macOS-only approach acceptable, or do you have plans to address this in a more general way across platforms?

2.Are there concerns about re-enabling Chromium UI components (such as the screen sharing infobar) that I might not have considered?

3.Would you recommend an alternative or more canonical solution to handle this issue?

4.Could you share your expected timeline or plan for resolving this problem officially, so we can align our workaround accordingly?

[ayushmanchhabra]

I only triage and help out if I can. Maybe @GnorTech can give some feedback

[AAdonis]

@ayushmanchhabra Thank you for the triage. @GnorTech , could you please share your thoughts on the questions I raised above? Specifically, we’d like to understand whether the macOS‑only approach is considered acceptable, and if there are plans for a more general cross‑platform solution. Any guidance on re‑enabling Chromium UI components, recommended alternatives, or your expected timeline would help us align our workaround accordingly.

[hthetiot]

@shikhak made a great initial PR for that in the right location to my understanding.
nwjs/chromium.src#165

This issue is similar to #8156, I believe.

[ayushmanchhabra]

Duplicate of #8156