exo::CompositorFrameSinkHolder's release callbacks hold ref

components/exo/compositor_frame_sink_holder.h

Index: components/exo/compositor_frame_sink_holder.h
diff --git a/components/exo/compositor_frame_sink_holder.h b/components/exo/compositor_frame_sink_holder.h
index 59cc9879e8908be5adeeae3adf1a92fa5b83bd4c..d79f720d6dc41e4dc7665fe460931dc7d079cf68 100644
--- a/components/exo/compositor_frame_sink_holder.h
+++ b/components/exo/compositor_frame_sink_holder.h
@@ -10,7 +10,7 @@
 #include <memory>
 
 #include "cc/ipc/mojo_compositor_frame_sink.mojom.h"
-#include "cc/resources/single_release_callback.h"
+#include "cc/resources/release_callback.h"
 #include "cc/resources/transferable_resource.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "components/exo/compositor_frame_sink.h"
@@ -37,9 +37,9 @@ class CompositorFrameSinkHolder
       cc::mojom::MojoCompositorFrameSinkClientRequest request);
 
   bool HasReleaseCallbackForResource(cc::ResourceId id);
-  void AddResourceReleaseCallback(
+  void SetResourceReleaseCallback(
       cc::ResourceId id,
-      std::unique_ptr<cc::SingleReleaseCallback> callback);
+      std::unique_ptr<cc::ReleaseCallback> callback);
 
   CompositorFrameSink* GetCompositorFrameSink() { return frame_sink_.get(); }
 
@@ -72,21 +72,17 @@ class CompositorFrameSinkHolder
   // Overridden from SurfaceObserver:
   void OnSurfaceDestroying(Surface* surface) override;
 
+ protected:
+  ~CompositorFrameSinkHolder() override;
+
  private:
   friend class base::RefCounted<CompositorFrameSinkHolder>;
 
-  ~CompositorFrameSinkHolder() override;
-
   void UpdateNeedsBeginFrame();
 
-  // Each release callback holds a reference to the CompositorFrameSinkHolder
-  // itself to keep it alive. Running and erasing the callbacks might result in
-  // the instance being destroyed. Therefore, we should not access any member
-  // variables after running and erasing the callbacks.
+  // A collection of callbacks used to release resources.
   using ResourceReleaseCallbackMap =
-      std::map<int,
-               std::pair<scoped_refptr<CompositorFrameSinkHolder>,
-                         std::unique_ptr<cc::SingleReleaseCallback>>>;
+      std::map<int, std::unique_ptr<cc::ReleaseCallback>>;
   ResourceReleaseCallbackMap release_callbacks_;
 
   Surface* surface_;