Extraer código fuente de web

uses Wininet;
 
 
function InternetReadWeb(URL: String): String;
var
  hNet:       pointer;
  hUrl:       pointer ;
  Buffer:     array [0..255] of char;
  BytesRead:  DWORD;
  NoError:    boolean;
  Ind:       integer;
begin
  BytesRead:= 0;
  Result:= '';
 
  if InternetAttemptConnect(0) <> ERROR_SUCCESS then exit;
 
  hNet:= InternetOpen('agent', INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
  if hNet <> nil then
  begin
    hUrl:= InternetOpenUrl(hNet, PCHAR(URL), nil, 0, INTERNET_FLAG_RELOAD, 0);
    if hUrl <> nil then
    begin
      // Lee la pagina web...
      ind:=0;
      repeat
        NoError:= InternetReadFile(hUrl, @Buffer[0], sizeof(Buffer)-1, BytesRead);
        if NoError and (BytesRead = 0) then break;
        Buffer[BytesRead]:= #0;
        Result:= Result + String(Buffer);
        inc(ind, BytesRead);
      until NoError and (BytesRead=0);
      InternetCloseHandle(hUrl);
    end;
    InternetCloseHandle(hNet);
  end;
end;
 
procedure TForm1.Button3Click(Sender: TObject);
begin
  Memo1.Text:= InternetReadWeb('https://developers.google.com/search/docs/advanced/security/https?hl=es');
end;