chrome/browser/resources/tab_strip/alert_indicator.html

<style>
  :host {
    -webkit-mask: center / contain no-repeat;
    background-color: currentColor;
    display: block;
    height: 100%;
    overflow: hidden;
    width: 16px;
  }

  :host([alert-state_='media-recording']),
  :host([alert-state_='desktop-capturing']) {
    -webkit-mask-image: url(alert_indicators/tab_media_recording.svg);
    background-color: var(--tabstrip-indicator-recording-color);
  }

  :host([alert-state_='tab-capturing']) {
    -webkit-mask-image:
        url(alert_indicators/tab_media_capturing_with_arrow.svg);
    background-color: var(--tabstrip-indicator-capturing-color);
  }

  :host([alert-state_='audio-playing']) {
    -webkit-mask-image: url(alert_indicators/tab_audio_rounded.svg);
  }

  :host([alert-state_='audio-muting']) {
    -webkit-mask-image: url(alert_indicators/tab_audio_muting_rounded.svg);
  }

  :host([alert-state_='bluetooth-connected']) {
    -webkit-mask-image: url(alert_indicators/tab_bluetooth_connected.svg);
  }

  :host([alert-state_='usb-connected']) {
    -webkit-mask-image: url(alert_indicators/tab_usb_connected.svg);
    -webkit-mask-size: 20px;
  }

  :host([alert-state_='hid-connected']) {
    -webkit-mask-image: url(alert_indicators/tab_hid_connected.svg);
  }

  :host([alert-state_='serial-connected']) {
    -webkit-mask-image: url(alert_indicators/serial_port.svg);
  }

  :host([alert-state_='pip-playing']) {
    -webkit-mask-image: url(alert_indicators/picture_in_picture_alt.svg);
    background-color: var(--tabstrip-indicator-pip-color);
  }

  :host([alert-state_='vr-presenting']) {
    -webkit-mask-image: url(alert_indicators/vr_headset.svg);
  }
</style>