Decorate PageCache instead of overriding definition

This is looking good and working well, but I'd perform a small tweak.

Thanks!

I ran into an issue with a custom module and another contrib module while both tried to decorate the page cache service. Our code was similar to this update, so I'm curious if this has been tested in a similar environment before being marked RTBC. I'm also curious about the status of this issue while tests are failing.

You could consider testing with Tome to confirm there are no issues with the service decoration:
https://www.drupal.org/project/tome/issues/3499452 🐛 ResettablePageCache overrides other service decorators Active

Tome Static has a "ResettablePageCache" that provides a "reset()" method. The code in the PR suggests this additional method could be lost if Big Pipe is the outer service (which seems to be the intent with a decoration priority of -1000). Any other inner service decorators that define new methods would also be affected.