Revert "use linear segment instead of recalculating it"

This reverts commit 86807d30cc2951021e81dc4507a5c14b37aebd31.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> use linear segment instead of recalculating it
> 
> Change-Id: I55f8e5d23f7f77681f45cfe2255ef8dda416497f
> Reviewed-on: https://skia-review.googlesource.com/123583
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> Commit-Queue: Mike Klein <mtklein@google.com>
> Auto-Submit: Mike Klein <mtklein@chromium.org>

TBR=mtklein@chromium.org,mtklein@google.com,brianosman@google.com

Change-Id: Ia4703dcaea1b58a9791e7907078a8c6af588539a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/123680
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
6 files changed