ccpr: Don't require flat interpolation
ccpr: Don't require flat interpolation

This requirement should have been removed at the time we switched to

Interpolation::kCanBeFlat.
Bug: skia:
Change-Id: I0b6d548e8a0fa691bb94d8169ba1c1c064f8f61d
Reviewed-on: https://skia-review.googlesource.com/154848
Reviewed-by: Greg Daniel <39df0a804564ccb6cf75f18db79653821f37c1c5@google.com>
Commit-Queue: Chris Dalton <ef7fc3a08ada7d31f16e9a18b5f3c728256e041e@google.com>

HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,rubenvb/skia,HalCanary/skia-hc,rubenvb/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,google/skia,rubenvb/skia,google/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,google/skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,rubenvb/skia,rubenvb/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia