[skottie] Add support for comp time remapping

  - plumb the framerate in AttachContext (needed for remapping)
  - expand CompTimeMapper to handle time remapping (in addition to
    time start, time stretch)

TBR=
Change-Id: If33bae7b4fe224f45d5a094a47899b9025827991
Reviewed-on: https://skia-review.googlesource.com/138990
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed