exo::CompositorFrameSinkHolder's release callbacks hold ref

components/exo/buffer.h

Index: components/exo/buffer.h
diff --git a/components/exo/buffer.h b/components/exo/buffer.h
index e7b5b605c45e423e78ce5ce91cf92ee346110338..bd1e1bfd848eb70c2e9a9b57f0c3a0a5df8282f7 100644
--- a/components/exo/buffer.h
+++ b/components/exo/buffer.h
@@ -29,6 +29,8 @@ class GpuMemoryBuffer;
 
 namespace exo {
 
+class CompositorFrameSinkHolder;
+
 // This class provides the content for a Surface. The mechanism by which a
 // client provides and updates the contents is the responsibility of the client
 // and not defined as part of this class.
@@ -56,7 +58,8 @@ class Buffer : public base::SupportsWeakPtr<Buffer> {
   std::unique_ptr<cc::SingleReleaseCallback> ProduceTextureMailbox(
       cc::TextureMailbox* mailbox,
       bool secure_output_only,
-      bool client_usage);
+      bool client_usage,
+      CompositorFrameSinkHolder* compositor_frame_sink_holder);
 
   // This should be called when the buffer is attached to a Surface.
   void OnAttach();
@@ -123,6 +126,12 @@ class Buffer : public base::SupportsWeakPtr<Buffer> {
   // The client release callback.
   base::Closure release_callback_;
 
+  // The CompositorFrameSinkHolder that has the ReleaseCallback of this buffer

[reveman, 2017/01/02 19:57:56]

please updated this comment after addressing my other comments.

+  // produced in ProduceTextureMailbox().
+  // Buffer holds a reference to the CompositorFrameSinkHolder to keep it alive.
+  // The refptr is reset when the release callback is called.
+  scoped_refptr<CompositorFrameSinkHolder> compositor_frame_sink_holder_;
+
   DISALLOW_COPY_AND_ASSIGN(Buffer);
 };