DM+nanobench: print both current and max RSS.

out/Debug/dm:
    ( 360/380 MB  2112) 396ms   gpu gm  xfermodes

out/Release/nanobench:
    32/33  MB 1659    2.46µs  2.55µs  2.54µs  2.67µs  2%  ▄▄▄▅▅▃▂▁▂█  gpu gradient_conicalZero_clamp_hicolor

out/Debug/nanobench:
    42/42  MB   desk_css3gradients.skp_1    8888

BUG=skia:

NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1115203002
3 files changed