Add SkShaderMaskFilter.h to public header list
Add SkShaderMaskFilter.h to public header list

Change-Id: I53a927e743d908ed5ce136a0f9eb9887753e1317
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/222779
Commit-Queue: Florin Malita <a8262bf13ea8c26821e91ea9bca6740a77c96dcd@chromium.org>
Commit-Queue: Mike Reed <f5cabf8735907151a446812c9875d6c0c712d847@google.com>
Auto-Submit: Florin Malita <a8262bf13ea8c26821e91ea9bca6740a77c96dcd@chromium.org>
Reviewed-by: Mike Reed <f5cabf8735907151a446812c9875d6c0c712d847@google.com>

google/skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia