Force use of and cache render surface.

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index 9d00f20fa754873b6df2c552c09e5b85c97eac9f..6f2ac6c5b6a06c625c14d91316b7f104d99d4cf6 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -626,6 +626,7 @@ void Layer::SwitchToLayer(scoped_refptr<cc::Layer> new_layer) {
   new_layer->SetTransform(cc_layer_->transform());
   new_layer->SetPosition(cc_layer_->position());
   new_layer->SetBackgroundColor(cc_layer_->background_color());
+  new_layer->SetCacheRenderSurface(cc_layer_->cache_render_surface());
 
   cc_layer_ = new_layer.get();
   content_layer_ = NULL;
@@ -654,6 +655,15 @@ void Layer::SwitchCCLayerForTest() {
   content_layer_ = new_layer;
 }
 
+// Note: The code that sets this flag would be responsible to unset it on that
+// ui::Layer. We do not want to clone this flag to a cloned layer by accident,
+// which could be a supprise. But we want to preserve it after switching to a
+// new cc::Layer. There could be a whole subtree and the root changed, but does
+// not mean we want to treat the cache all different.
+void Layer::SetCacheRenderSurface(bool cache_render_surface) {
+  cc_layer_->SetCacheRenderSurface(cache_render_surface);
+}
+
 void Layer::SetTextureMailbox(
     const viz::TextureMailbox& mailbox,
     std::unique_ptr<viz::SingleReleaseCallback> release_callback,