only build stats bar chart when it'll be printed

I keep seeing it show up on the profile(usually under memmove) of tight
benchmarks and it's kind of distracting.  We don't even print it when
we pass --quiet, so that seems like a nice way to stifle it.

Change-Id: I3a67a7ca1758fd35e3b63cfeeddeac4ff1ffe38d
Reviewed-on: https://skia-review.googlesource.com/157520
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed