ubsan shift fixes

src/effects/gradients/SkGradientShaderPriv.h

Index: src/effects/gradients/SkGradientShaderPriv.h
diff --git a/src/effects/gradients/SkGradientShaderPriv.h b/src/effects/gradients/SkGradientShaderPriv.h
index 203f791ceb80999b7043afddad735ede30d2a636..f8a968d1a2516e54ab8d30b34e2fde5e368532fc 100644
--- a/src/effects/gradients/SkGradientShaderPriv.h
+++ b/src/effects/gradients/SkGradientShaderPriv.h
@@ -58,7 +58,7 @@ static inline SkFixed repeat_tileproc(SkFixed x) {
 #endif
 
 static inline SkFixed mirror_tileproc(SkFixed x) {
-    int s = x << 15 >> 31;
+    int s = SkLeftShift(x, 15) >> 31;
     return (x ^ s) & 0xFFFF;
 }