To clarify:

We create the headless browser with navigation controls, but initially without a virtual time policy. Once the first navigation request comes in, we set up virtual time and, in the callback, allow the navigation.

For any subsequent request that goes to a different domain, this happens:

1. navigationRequested fires
2. client calls setVirtualTimePolicy
3. In https://cs.chromium.org/chromium/src/content/browser/devtools/render_frame_devtools_agent_host.cc, the messages are buffered due to a pending navigation

... Now, there's a deadlock, because the embedder is waiting for the callback of setVirtualTimePolicy, and the devtools agent waits for the navigation to go through to handle any other pending messages.

To add one more detail, IIRC the buffering happens because the navigation could result in a new renderer getting spawned and we don't want the commands following the navigation ending up in the old renderer.

We could either document this limitation or perhaps come up with a way to set a default virtual time policy for new pages/renderers so the call would become unnecessary. Alternatively we could change the render process policy to keep everything in the same renderer which would remove the need to buffer commands.

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

*** UI Mass Triage ***

Closing due to inactivity, feel free to reopen if needed.