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 89602807c8cfc58626b3b81f10f9e7de684fc8e4..0bd2faedf395a46e523719cc1b1909d022202749 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -405,6 +405,12 @@ class COMPOSITOR_EXPORT Layer
     return frame_size_in_dip_;
   }
 
+  // Force use of 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 SetForceRenderSurface(bool force);
+
  private:
   friend class LayerOwner;
   class LayerMirror;