Add helper SkMatrix44::hasPerspective()

include/utils/SkMatrix44.h

Index: include/utils/SkMatrix44.h
diff --git a/include/utils/SkMatrix44.h b/include/utils/SkMatrix44.h
index 26247a01e99c0aa19dad0152d61309d1c75b577e..83b5443d681cc548e3f001bcdeebe20c15ffbd41 100644
--- a/include/utils/SkMatrix44.h
+++ b/include/utils/SkMatrix44.h
@@ -198,6 +198,10 @@ public:
         return !(this->getType() & ~(kScale_Mask | kTranslate_Mask));
     }
 
+    inline bool hasPerspective() const {
+        return SkToBool(this->getType() & kPerspective_Mask);
+    }
+
     void setIdentity();
     inline void reset() { this->setIdentity();}