Provide a placeholder queue ID for the custom embedder task runner. (#11062)

This issue would only manifest when a custom task runner was being used with
a custom compositor. Both were tested separately but not together. A new
test has been added for this. We still create the GPU thread merger
unnecessarily but I can patch that later. I also cleaned up the existing
custom task runner test to not submit tasks on a dead engine as they just
log errors unnecessarily.

Filed new: https://github.com/flutter/flutter/issues/38844
https://dart.googlesource.com/external/github.com/flutter/engine/+/99ee3c2b0df7911baa390fa897cefc836605d154
1 file changed
tree: a2452d678ad0b69d1ece2cea8530b7b1c36a7225
  1. commits.json