Add support for Canvas flags on save.

This is required for the rewrite of layers support.

Change-Id: I5c0867dcf5aeb0392c8d0fbab05febb0eaff70d9
diff --git a/libs/hwui/SkiaShader.cpp b/libs/hwui/SkiaShader.cpp
index c7a01b1..a5e0f78 100644
--- a/libs/hwui/SkiaShader.cpp
+++ b/libs/hwui/SkiaShader.cpp
@@ -167,12 +167,12 @@
         shaderMatrix.mapPoint(start.left, start.top);
         shaderMatrix.mapPoint(start.right, start.bottom);
     }
-    snapshot.transform.mapRect(start);
+    snapshot.transform->mapRect(start);
 
     const float gradientX = start.right - start.left;
     const float gradientY = start.bottom - start.top;
 
-    mat4 screenSpace(snapshot.transform);
+    mat4 screenSpace(*snapshot.transform);
     screenSpace.multiply(modelView);
 
     // Uniforms