Chrome Version       : 51.0.2704.19

app_list_service_win.cc has:

#if defined(GOOGLE_CHROME_BUILD)
void SetDidRunForNDayActiveStats() {
  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
  base::FilePath exe_path;
  if (!PathService::Get(base::DIR_EXE, &exe_path)) {
    NOTREACHED();
    return;
  }
  bool system_install = !InstallUtil::IsPerUserInstall(exe_path);
  // Using Chrome Binary dist: Chrome dist may not exist for the legacy
  // App Launcher, and App Launcher dist may be "shadow", which does not
  // contain the information needed to determine multi-install.
  // Edge case involving Canary: crbug/239163.
  BrowserDistribution* chrome_binaries_dist =
      BrowserDistribution::GetSpecificDistribution(
          BrowserDistribution::CHROME_BINARIES);
  if (chrome_binaries_dist &&
      InstallUtil::IsMultiInstall(chrome_binaries_dist, system_install)) {
    UpdatingAppRegistrationData app_launcher_reg_data(
        installer::kAppLauncherGuid);
    GoogleUpdateSettings::UpdateDidRunStateForApp(
        app_launcher_reg_data, true /* did_run */);
  }
}
#endif  // GOOGLE_CHROME_BUILD


We need to ensure any stuff this adds to the registry isn't left behind when the app launcher is turned down.