Wire up SurfaceView stretch effect

Bug: 179047472
Test: StretchySurfaceViewActivity

Change-Id: I7f3d582cc66fb732a557e9332edc6d186db2335c
diff --git a/libs/hwui/TreeInfo.h b/libs/hwui/TreeInfo.h
index f2481f8..cc9094c 100644
--- a/libs/hwui/TreeInfo.h
+++ b/libs/hwui/TreeInfo.h
@@ -98,6 +98,8 @@
 
     const SkISize screenSize;
 
+    int stretchEffectCount = 0;
+
     struct Out {
         bool hasFunctors = false;
         // This is only updated if evaluateAnimations is true