Refactor DisplayList path caching.

This removes dependence on SkPath ptrs that HWUI does not control
the lifecycle of. This clears up some errors where the paths are
not generated from Java, but rather the Skia test suites.

Cherry-pick of a change that originally landed in master-skia and is
dependent on a skia merge (ag/655422).

Change-Id: I41b9797a2b0af5d6b4ea51891565469d4f1d832d
diff --git a/libs/hwui/DisplayList.h b/libs/hwui/DisplayList.h
index 011b509..3178584 100644
--- a/libs/hwui/DisplayList.h
+++ b/libs/hwui/DisplayList.h
@@ -134,12 +134,11 @@
     int projectionReceiveIndex;
 
     Vector<const SkBitmap*> bitmapResources;
+    Vector<const SkPath*> pathResources;
     Vector<const Res_png_9patch*> patchResources;
 
     std::vector<std::unique_ptr<const SkPaint>> paints;
     std::vector<std::unique_ptr<const SkRegion>> regions;
-    std::vector<std::unique_ptr<const SkPath>> paths;
-    SortedVector<const SkPath*> sourcePaths;
     Vector<Functor*> functors;
 
     const Vector<Chunk>& getChunks() const {