Fix infinite matrix during an invert.

include/utils/SkMatrix44.h

Index: include/utils/SkMatrix44.h
diff --git a/include/utils/SkMatrix44.h b/include/utils/SkMatrix44.h
index 90f29a994a77eeb480500c6e1345ae1a76e7aeaf..2a698f52a23fe5db7eac10bd8fef99bb7e26ad7e 100644
--- a/include/utils/SkMatrix44.h
+++ b/include/utils/SkMatrix44.h
@@ -358,7 +358,8 @@ public:
     }
 
     /** If this is invertible, return that in inverse and return true. If it is
-        not invertible, return false and ignore the inverse parameter.
+        not invertible, return false and leave the inverse parameter in an
+        unspecified state.
      */
     bool invert(SkMatrix44* inverse) const;