Revert of Boost GrGLConicEffect's variables to all high precision (patchset #1 id:1 of https://codereview.chromium.org/1513483002/ )

Reason for revert:
Broke build

Original issue's description:
> Boost GrGLConicEffect's variables to all high precision
>
> BUG=555779
>
> Committed: https://skia.googlesource.com/skia/+/624c59a1c7af38eb83e803f345a6f3e225475a08

TBR=egdaniel@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=555779

Review URL: https://codereview.chromium.org/1514553002
2 files changed