UI resource are evicted when LTH is set to not visible.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 31870ac48bd1e5e290fc620bbe1cf495903ec875..7642fa43cf86717b58315c7c54430e1fe6ac3798 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -383,6 +383,9 @@ class CC_EXPORT LayerTreeHostImpl
   // Deletes a UI resource.  May safely be called more than once.
   void DeleteUIResource(UIResourceId uid);
 
+  // Release all the UI resources.
+  void ReleaseUIResources();
+
   ResourceProvider::ResourceId ResourceIdForUIResource(UIResourceId uid) const;
 
  protected:
@@ -555,6 +558,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   bool need_to_update_visible_tiles_before_draw_;
 
+  bool ui_resources_evicted_;
+
   // Optional callback to notify of new tree activations.
   base::Closure tree_activation_callback_;