Description of Change

Closes #23665.

This PR enables the Windows Control Overlay API on Linux. To do so, we create a new subclass of FramelessView. This primarily follows logic from upstream's implementation with modifications for our use case and stripped of logic irrelevant to Electron.

cc @bpasero @deepak1556

Todo:

• Ensure existing WCO tests pass
• Test with RTL and LTR
• Test that color can be changed dynamically
• Test that height can be changed dynamically

Functionality on Wayland will be approached as a follow-up as I don't currently have the requisite hardware to test this.

const { app, BrowserWindow } = require('electron');

async function createWindow () {
  const mainWindow = new BrowserWindow({
    titleBarOverlay: {
      color: '#0000f0',
      symbolColor: '#f54260'
    },
    titleBarStyle: 'hidden'
  });

  await mainWindow.loadURL('data:text/html,<h1>Hello, World!</h1>');

  setTimeout(() => {
    console.log('Setting title bar overlay color!!!');
    mainWindow.setTitleBarOverlay({
      color: '#355E3B',
      symbolColor: '#99aebd',
      height: 40
    });
  }, 3000);
}

app.whenReady().then(() => {
  createWindow();

  app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) createWindow();
  });
});

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') app.quit();
});

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation, tutorials, templates and examples are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Enabled the Windows Control Overlay API on Linux.