How do I instantiate policies in Chrome on mac?

This is the set of policies that I want for my installation of Chrome (converted to json):

{
   "chromePolicies": {
      "BrowserAddPersonEnabled": {
         "level": "recommended",
         "scope": "machine",
         "source": "platform",
         "value": false
      },
      "BrowserGuestModeEnabled": {
         "level": "recommended",
         "scope": "machine",
         "source": "platform",
         "value": false
      },
      "ExtensionInstallForcelist": {
         "level": "mandatory",
         "scope": "machine",
         "source": "platform",
         "value": [ "pncfbmialoiaghdehhbnbhkkgmjanfhe", "mdnleldcmiljblolnjhpnblkcekpdkpa", "cjpalhdlnbpafiamejdnhcphjbkeiagm" ]
      }
   }
}

I’ve tried to instantiate these policies in a number of ways, including:

1. Edited the com.google.Chrome.plist in /Library/Managed Preferences/Preferences
2. Edited the com.google.Chrome.plist in /Library/Preferences
3. Ran these commands:

defaults write com.google.Chrome BrowserAddPersonEnabled -bool false
defaults write com.google.Chrome BrowserGuestModeEnabled -bool false
defaults write com.google.Chrome ExtensionInstallForcelist -array 
  '{ pncfbmialoiaghdehhbnbhkkgmjanfhe; }' 
  '{ mdnleldcmiljblolnjhpnblkcekpdkpa; }' 
  '{ cjpalhdlnbpafiamejdnhcphjbkeiagm; }'

4. Installed mcxToProfile and converted my policies file to a profile and then installed that profile on my Mac OS, according to these instructions. That was with this command: python mcxToProfile.py --plist /Library/Preferences/com.google.Chrome.plist --identifier com.google.Chrome

Every time I edit the policies, they fail to stick. They might appear in Chrome for the current session but they go away after I restart my computer (specifically the extension install forcelist).