procedure TForm1.Button4Click(Sender: TObject; const browser: ICefBrowser;
  const frame: ICefFrame; httpStatusCode: Integer; out Result: Boolean );

begin
  if Assigned(frame) then
    frame.VisitDomProc(OnExploreDOM);
end;

procedure MinimizeClickEvent(const AEvent: ICefDomEvent);
begin
  ShowMessage('Here the application can be minimized.');
end;

procedure OnExploreDOM(const ADocument: ICefDomDocument);
var
  DOMNode: ICefDomNode;
begin
  // here we attempt to find our "minimize" element
  DOMNode := ADocument.GetElementByClassName('_2UaNq _3mMX1');
  // and if we find it, we attach to its click event our MinimizeClickEvent
  // procedure so whenever the element will be clicked, that procedure will
  // execute
  if Assigned(DOMNode) then
    DOMNode.AddEventListenerProc('click', True, MinimizeClickEvent);
end;