code: private boolean mute() {
      isMuted = true;
      setSoundChipText(getContext().getString(R.string.muted));
      showSoundChip();
      soundFabOff();
      return isMuted;
    }
docs: Sets up mute UI event.
  <p>
  Shows chip with "Muted" text.
  Changes sound {@link FloatingActionButton}
  {@link android.graphics.drawable.Drawable} to denote sound is off.
  <p>
  Sets private state variable to true (muted)
  
  @return true, view is in muted state