Managed extension policy not taking effect on some extension startups

[twschiller]

Describe the bug

• Managed policy wasn't taking effect on a browser profile startup (upon opening Chrome for after logging into a VDI)
• For the enterprise customer using SSO, this meant PixieBrix opened that standard login page vs. showing the SSO flow and restricting URLs according to the organization policy
• We have some logic to try to account for flakiness in when Chrome makes the policy available:

  pixiebrix-extension/src/store/enterprise/managedStorage.ts

  Line 59 in 9fa424d

  const waitForInitialManagedStorage = pMemoize(async () => {

• However, some of the code won't recover from the policy not being found on initial startup
• When we checked the chrome://policy page, the settings were there. So it looks like the policy came through but our extension wasn't aware of it on initial startup
• When we closed Chrome and re-opened it, it worked as expected

Discussion

• The challenge of adding blocking for reading the managed storage policy is that it delays showing login screen for normal users who don't need the policy

To Reproduce

• Can't reproduce reliably due to flakiness of managed storage

Actual behavior

A clear and concise description of what happened that shouldn't

Expected behavior

• PixieBrix reads the policy and opens SSO flow and applies organization restrictions

Desktop (please complete the following information):

• OS: Windows (which version?)
• Browser: Chrome
• Extension Version: 1.8.8

[twschiller]

I opened a w3c issue here to try to get clarity on intended behavior: w3c/webextensions#547