SkTypes: extract SkTo

Change-Id: I8de790d5013db2105ad885fa2683303d7c250b09
Reviewed-on: https://skia-review.googlesource.com/133620
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/src/utils/mac/SkCreateCGImageRef.cpp b/src/utils/mac/SkCreateCGImageRef.cpp
index 95c48b1..623b3e7 100644
--- a/src/utils/mac/SkCreateCGImageRef.cpp
+++ b/src/utils/mac/SkCreateCGImageRef.cpp
@@ -8,9 +8,10 @@
 #include "SkTypes.h"
 #if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
 
-#include "SkCGUtils.h"
 #include "SkBitmap.h"
+#include "SkCGUtils.h"
 #include "SkColorData.h"
+#include "SkTo.h"
 
 static CGBitmapInfo ComputeCGAlphaInfo_RGBA(SkAlphaType at) {
     CGBitmapInfo info = kCGBitmapByteOrder32Big;