To see the flag in action, export GECKO_BLOCK_DEBUG_FLAGS="float-manager" and
open a page containing float elements. For example:
$ GECKO_BLOCK_DEBUG_FLAGS="float-manager" ./mach run layout/reftests/floats/orthogonal-floats-1a.html
MozReview-Commit-ID: 7Rb45ophewf
1.Remove NOISY_FIRST_LINE, NOISY_MAX_ELEMENT_SIZE, NOISY_MAXIMUM_WIDTH.
2.Remove REALLY_NOISY_FIRST_LINE.
Only one static function, which has no caller, but defined under this flag.
3.Move REALLY_NOISY_REFLOW_CHILD into REALLY_NOISY_REFLOW.
The chunk of REALLY_NOISY_REFLOW_CHILD seems dead for long time, so make it
alive by moving it under REALLY_NOISY_REFLOW.
MozReview-Commit-ID: E7IW0qStdck