Clean up deferredLayers only onGpuContextDestroyed.

Test: manual
bug:34919311
Change-Id: I5488b0845ec3922424f5893943e4f42675dfc9fd
diff --git a/libs/hwui/renderstate/RenderState.h b/libs/hwui/renderstate/RenderState.h
index a44fa9d..f78bf7a 100644
--- a/libs/hwui/renderstate/RenderState.h
+++ b/libs/hwui/renderstate/RenderState.h
@@ -99,8 +99,6 @@
         mActiveLayerUpdaters.erase(layerUpdater);
     }
 
-    void destroyLayersInUpdater();
-
     // TODO: This system is a little clunky feeling, this could use some
     // more thinking...
     void postDecStrong(VirtualLightRefBase* object);
@@ -121,6 +119,7 @@
 private:
     void interruptForFunctorInvoke();
     void resumeFromFunctorInvoke();
+    void destroyLayersInUpdater();
 
     explicit RenderState(renderthread::RenderThread& thread);
     ~RenderState();