Move BenchTimer to tools as Timer

This breaks a bunch of circular dependencies between tools and gm and bench.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/4ed75287aed6371c6e4a41ffcc78c8a49c9810ed

CQ_EXTRA_TRYBOTS=tryserver.skia:Build-Mac10.7-Clang-Arm7-Debug-iOS-Trybot,Test-Ubuntu12-ShuttleA-GTX660-x86-Debug-Trybot
R=tfarina@chromium.org, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/344213003
45 files changed