ComputeRowBytes must not overflow width when it shifts

src/core/SkBitmap.cpp

Index: src/core/SkBitmap.cpp
diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index 11c7cbd69c289991ea25c8894a6b62037ec34a2c..502d7db9b40c235b0865881b8acbb73e494019c2 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -190,10 +190,14 @@ size_t SkBitmap::ComputeRowBytes(Config c, int width) {
             break;
         case kRGB_565_Config:
         case kARGB_4444_Config:
-            rowBytes = width << 1;
+            // assign and then shift, so we don't overflow int
+            rowBytes = width;
+            rowBytes <<= 1;
             break;
         case kARGB_8888_Config:
-            rowBytes = width << 2;
+            // assign and then shift, so we don't overflow int
+            rowBytes = width;
+            rowBytes <<= 2;
             break;
         default:
             SkDEBUGFAIL("unknown config");