Pepper takes ownership of a mailbox before passing it to the texture layer.

gpu/ipc/client/command_buffer_proxy_impl.h

Index: gpu/ipc/client/command_buffer_proxy_impl.h
diff --git a/gpu/ipc/client/command_buffer_proxy_impl.h b/gpu/ipc/client/command_buffer_proxy_impl.h
index 453d7b790c506bed40a045bf75db93c895f2d77c..7980a58c58080125f63610f5f095929e31ea6cb4 100644
--- a/gpu/ipc/client/command_buffer_proxy_impl.h
+++ b/gpu/ipc/client/command_buffer_proxy_impl.h
@@ -114,7 +114,10 @@ class GPU_EXPORT CommandBufferProxyImpl
                        const base::Closure& callback) override;
   bool CanWaitUnverifiedSyncToken(const gpu::SyncToken* sync_token) override;
 
-  bool ProduceFrontBuffer(const gpu::Mailbox& mailbox);
+  void TakeFrontBuffer(const gpu::Mailbox& mailbox);
+  void ReturnFrontBuffer(const gpu::Mailbox& mailbox,
+                         const gpu::SyncToken& sync_token,
+                         bool is_lost);
 
   void AddDeletionObserver(DeletionObserver* observer);
   void RemoveDeletionObserver(DeletionObserver* observer);