In Chrome feature flags are meant to be set a single time with each desired flag seperated by commas. In the case where there are multiple enable-feature switches only the last one is used. At least I'm pretty sure based on what I read online and looking at the Chromium source code, I believe each time an enable-feature switch is seen it just overwrites the previously set value.

Ex:

# WRONG, WebRTCPipeWireCapturer is the only used value.
electron --enable-features=PulseaudioLoopbackForScreenShare --enable-features=WebRTCPipeWireCapturer ...
# RIGHT
electron --enable-features=PulseaudioLoopbackForScreenShare,WebRTCPipeWireCapturer ...

This PR essentially just stores the different the enable-feature switch values in a set instead of appending them immediately and at the end joins them together with commas and appends them. I extended this as well to disable-features, enable-blink-features, and disable-blink-features. I'm thinking of removing the disable-blink-features part, as Legcord doesn't set any flags on it. I was almost tempted to also add something for enable-hardware-overlays as it's used in the performance preset, but I restrained as I felt there's not much usecase and I didn't want to add another thing to the Preset type.

Unfortunately I had to stray into flags.ts to modify how the presets are applied to work with this, but I don't see how else I could have worked with it.

I have only tested this locally on my Arch install and I've noticed no issues based off of VERY brief testing. It works with the legcord-flags.conf pattern Arch does.

My workflow was mostly launching Legcord with --inspect and then using Chrome remote dev tools to run:

const { BrowserWindow } = require('electron');const win = new BrowserWindow();win.loadURL('chrome://gpu');

To see what the command line args were.

PS: I got hardware decoding working by following the same instructions for Chrome by doing --ozone-platform-hint=auto --enable-features=AcceleratedVideoDecodeLinuxGL