(This is a proactive bug filing, the reference CL(s) has not landed or been reviewed yet, I'm filing this bug for reference. tbarzic@, look at the bug after relevant CL(s) lands)

I'm about to change easyUnlockPrivate api's rest of the ExtensionFunction implementations to extend from UIThreadExtensionFunction, as part of nuking AsyncExtensionFunction (https://chromium-review.googlesource.com/c/chromium/src/+/994711 only for reference, and   https://crbug.com/829174  for AsyncExtensionFunction)

However, I'm not entirely certain about calls like:

GetCryptoDelegate(browser_context())->CreateSecureMessage(
      *params,
      base::Bind(&EasyUnlockPrivateCreateSecureMessageFunction::OnData,
                 this));

Right after this call, it would be better if we can say with certainty that OnData was called or not. I'm planning to use the existing hack for this for now:

return did_respond() ? AlreadyResponded() : RespondLater();