I'm trying to enable an optimization in Skia: https://chromium-review.googlesource.com/c/chromium/src/+/1333879

I expected layout test failures, which are fine. I was surprised by unit test failures related to the discardable memory allocator. Many unit tests never required discardable memory in the past. My change triggers use of discardable in a few new tests.

Following the pattern used in cc's unit tests, I updated the views unit tests (PS4). At this point, a few tests in interactive_ui_tests have the problem. However, adding a TestDiscardableMemoryAllocator to interactive_ui_tests_main (PS5) has made things worse - it looks like some tests do install a discardable allocator, so now we assert about double-installing one.

Did I go wrong somewhere in PS5? More importantly, is there something that can be done at a lower level to ensure discardable memory is configured for many/most/all unit tests?