While investigating this revert, a couple of concerning things were discovered wrt the Flutter test suite in the web.

1. The revert was caused because some tests failed when the scene of the HTML renderer started respecting the "overridden" value of devicePixelRatio to report its "logical size".

   • Bad behavior that fixed golden tests and allowed hostElement to reland was introduced here.
   • This used to work before because we were using the logical size directly from the window JS object, which doesn't care about overrides.

2. The devicePixelRatio overridden by flutter tests (3.0) does NOT match the devicePixelRatio set by the browser when it starts.

   • In fact, the browser is starting always with DPR=1. It should pass '--force-device-scale-factor=X' for other DPRs.

3. By hijacking the _matchers_web.dart file, it seems that the isCanvasKit boolean used there to determine how to match a golden never returns true (this might be a regression) Fixed by: Pass along web renderer into debugging options in the test command. #143128

TL;DR: The flutter test runner needs some love in the flutter/flutter repository.