enforce 16byte alignment in shader contexts

src/effects/gradients/SkTwoPointConicalGradient.cpp

Index: src/effects/gradients/SkTwoPointConicalGradient.cpp
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index 2209306fe3877b1d1106dd54fe881d6a99907a0a..f4b6b0c8b0ccac11c1fcb2d47ce2fdd2ffb7072b 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -211,8 +211,8 @@ bool SkTwoPointConicalGradient::isOpaque() const {
     return false;
 }
 
-size_t SkTwoPointConicalGradient::contextSize(const ContextRec&) const {
-    return sizeof(TwoPointConicalGradientContext);
+size_t SkTwoPointConicalGradient::onContextSize(const ContextRec&) const {
+    return SkAlign16(sizeof(TwoPointConicalGradientContext));
 }
 
 SkShader::Context* SkTwoPointConicalGradient::onCreateContext(const ContextRec& rec,