Add a test for installing Chrome at system level.

chrome/test/mini_installer/config/chrome_user_installed.prop

 {
   "Files": {
     "$LOCAL_APPDATA\\$CHROME_DIR\\Application\\chrome.exe": {"exists": true},
     "$LOCAL_APPDATA\\$CHROME_DIR\\Application\\$MINI_INSTALLER_FILE_VERSION\\chrome.dll":
         {"exists": true},
     "$LOCAL_APPDATA\\$CHROME_DIR\\Application\\$MINI_INSTALLER_FILE_VERSION\\Installer\\chrome.7z":
         {"exists": true},
     "$LOCAL_APPDATA\\$CHROME_DIR\\Application\\$MINI_INSTALLER_FILE_VERSION\\Installer\\setup.exe":
         {"exists": true}
   },
   "RegistryEntries": {
     "HKEY_CURRENT_USER\\$CHROME_UPDATE_REGISTRY_SUBKEY": {
       "exists": true,
       "values": {
         "pv": {"type": "SZ", "data": "$MINI_INSTALLER_FILE_VERSION"}
       }
     }
   }
 }