Fix a typo in SkISize comments

Change-Id: I94597214ea3c7e3c0b5f88c42378061f0d217da2
Reviewed-on: https://skia-review.googlesource.com/157400
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: Nathan Rogers <nathanrogers@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/include/core/SkSize.h b/include/core/SkSize.h
index 061e3c4..4486e36 100644
--- a/include/core/SkSize.h
+++ b/include/core/SkSize.h
@@ -24,7 +24,7 @@
      */
     bool isZero() const { return 0 == fWidth && 0 == fHeight; }
 
-    /** Returns true if either widht or height are <= 0 */
+    /** Returns true if either width or height are <= 0 */
     bool isEmpty() const { return fWidth <= 0 || fHeight <= 0; }
 
     /** Set the width and height to 0 */