clean up useage of SkFloatBits

Bug: skia:
Change-Id: I6d3a0019f2fcf11feca69123e4ce6eb35de43613
Reviewed-on: https://skia-review.googlesource.com/31222
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
7 files changed