Support transform'd GraphicBuffers

Bug: 28428955
Change-Id: I23e2fc9b96a67c7cfda42d9d7319e478194a7fa7
diff --git a/libs/hwui/Matrix.h b/libs/hwui/Matrix.h
index 36007cd..9cde5d6 100644
--- a/libs/hwui/Matrix.h
+++ b/libs/hwui/Matrix.h
@@ -236,6 +236,8 @@
 
     static const Matrix4& identity();
 
+    void invalidateType() { mType = kTypeUnknown; }
+
 private:
     mutable uint8_t mType;