Since people seem to write "2 ^ X" hoping that it means "1 << X", clang
recently added a warning for this pattern.
It incorrectly fires on this file. To suppress it, restructure the code
to be less clever. (Alternatively we could use "xor" instead of "^" or
write "0x2" instead of "2" but both seem worse.)
No intended behavior change.
Bug: chromium:995200
Change-Id: I64744345be5f5a8cd1f4aaeaf0982da239b378a7