add decal tilemode to shaders

Plenty more to follow-up:
- gradients
- gpu impl

Bug: skia:7638
Change-Id: I8e54fd0e24921f040f178c793b36c7fb855b136e
Reviewed-on: https://skia-review.googlesource.com/107420
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/src/jumper/SkJumper.h b/src/jumper/SkJumper.h
index ab95cc0..1429458 100644
--- a/src/jumper/SkJumper.h
+++ b/src/jumper/SkJumper.h
@@ -69,6 +69,12 @@
     float invScale; // cache of 1/scale
 };
 
+struct SkJumper_DecalTileCtx {
+    uint32_t mask[SkJumper_kMaxStride];
+    float    limit_x;
+    float    limit_y;
+};
+
 struct SkJumper_CallbackCtx {
     MAYBE_MSABI void (*fn)(SkJumper_CallbackCtx* self, int active_pixels/*<= SkJumper_kMaxStride*/);