exo: Recreate Surface resources on context lost.

components/exo/buffer.h

Index: components/exo/buffer.h
diff --git a/components/exo/buffer.h b/components/exo/buffer.h
index 6502cdfa2efae22697c71370cfbf7748e942be4f..36077283465c35f64fa30238d9c7f4f4fc2f0cb9 100644
--- a/components/exo/buffer.h
+++ b/components/exo/buffer.h
@@ -56,11 +56,13 @@ class Buffer : public base::SupportsWeakPtr<Buffer> {
   // This function can be used to acquire a texture mailbox for the contents of
   // buffer. Returns a release callback on success. The release callback should
   // be called before a new texture mailbox can be acquired unless
-  // |non_client_usage| is true.
+  // |non_client_usage| is true. |detach_callback| receives a callback that
+  // should be called when the buffer is detached from the current surface.
   std::unique_ptr<cc::SingleReleaseCallback> ProduceTextureMailbox(
       cc::TextureMailbox* mailbox,
       bool secure_output_only,
-      bool client_usage);
+      bool client_usage,
+      base::Closure* detach_callback);

[reveman, 2016/06/22 17:15:26]

hm, I see how this works but it took a minute for me to understand it.

Instead of returning a callback here. What do you think about just adding two
functions to the Buffer class, OnAttach+OnDetach and just call those directly
from the Surface class when appropriate? Potentially adding some private
BufferAttachment utility class to exo::Surface to handle the call to OnDetach
automatically. OnAttach/Detach can keep a attachment count and that we can also
improve debug output by logging something when a buffer is attached to two
different surfaces.

[jbauman, 2016/06/22 23:45:48]

Done.

 
   // Returns the size of the buffer.
   gfx::Size GetSize() const;