To test that Site Isolation is in effect, one can follow the steps below:
1. Navigate to a website that hosts cross-site frames. For example:
1.b. Click "Go cross-site (complex page)" button
2. Open Chrome's Task Manager: Menu -> More tools -> Task manager (Shift+Esc)
3. Verify that separate rows exist for frames in different processes. For example:
I hope this helps. Let us know if you have any further questions.
-Lukasz