ubsan shift fixes

src/core/SkBitmapProcState_matrixProcs.cpp

Index: src/core/SkBitmapProcState_matrixProcs.cpp
diff --git a/src/core/SkBitmapProcState_matrixProcs.cpp b/src/core/SkBitmapProcState_matrixProcs.cpp
index ee61ee8556c1dd7a398c7c316640f8b64924ec39..1c4b7b6bcf4c1b9f79834f8a7889e6ed12d6a7e9 100644
--- a/src/core/SkBitmapProcState_matrixProcs.cpp
+++ b/src/core/SkBitmapProcState_matrixProcs.cpp
@@ -178,7 +178,7 @@ static inline U16CPU fixed_repeat(SkFixed x) {
 #endif
 
 static inline U16CPU fixed_mirror(SkFixed x) {
-    SkFixed s = x << 15 >> 31;
+    SkFixed s = SkLeftShift(x, 15) >> 31;
     // s is FFFFFFFF if we're on an odd interval, or 0 if an even interval
     return (x ^ s) & 0xFFFF;
 }