Force use of and cache render surface.

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index 9cf998d9a8e7bf036d601b56c734ec45253b99e6..5ab924eb7edee5a85d16fe5bbef47a87287adba6 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -411,6 +411,12 @@ class COMPOSITOR_EXPORT Layer
     return frame_size_in_dip_;
   }
 
+  // Force use of and cache render surface. Note that this also disables
+  // occlusion culling in favor of efficient caching. This should
+  // only be used when paying the cost of creating a render
+  // surface even if layer is invisible is not a problem.
+  void SetCacheRenderSurface(bool cache_render_surface);
+
  private:
   friend class LayerOwner;
   class LayerMirror;