[identity] Don't abort launchWebAuthFlow if an iframe fails to navigate

chrome.identity.launchWebAuthFlow() observes all navigations in the
provider's auth flow. Chrome stops the auth flow if one of the
navigations fails, assuming that the provider's auth URL cannot be load.
This also includes navigations in sub-frames.

Dropbox auth provider inserts <iframe>s with ReCAPTCHA challenges on
their auth page. For some reason, this page decides to remove an iframe
before it commits a navigation, making launchWebAuthFlow() abort the auth
flow.

This restriction looks unnecessary and prevents launchWebAuthFlow work
with Dropbox auth provider. This CL stops launchWebAuthFlow() observing
navigations in subframes.

Bug: 1049565
Change-Id: I5b596466bc69410b12150221c456d1777106c0d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2054226
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741060}
1 file changed