[Reland 1] Pepper takes ownership of a mailbox before passing it to the texture layer.

components/mus/public/interfaces/command_buffer.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module mus.mojom;
 
 import "gpu/ipc/common/capabilities.mojom";
 import "gpu/ipc/common/command_buffer.mojom";
 import "gpu/ipc/common/mailbox.mojom";
 import "gpu/ipc/common/sync_token.mojom";
@@ skipping 33 matching lines @@
   DestroyTransferBuffer(int32 id);
   CreateImage(int32 id,
               handle memory_handle,
               int32 type,
               mojo.Size size,
               int32 format,
               int32 internal_format);
   DestroyImage(int32 id);
   CreateStreamTexture(uint32 client_texture_id)
       => (int32 stream_id, bool succeeded);
-  ProduceFrontBuffer(gpu.mojom.Mailbox mailbox);
+  TakeFrontBuffer(gpu.mojom.Mailbox mailbox);
+  ReturnFrontBuffer(gpu.mojom.Mailbox mailbox, bool is_lost);
   SignalQuery(uint32 query, uint32 signal_id);
   SignalSyncToken(gpu.mojom.SyncToken sync_token, uint32 signal_id);
   WaitForGetOffsetInRange(int32 start, int32 end)
       => (gpu.mojom.CommandBufferState state);
   WaitForTokenInRange(int32 start, int32 end)
       => (gpu.mojom.CommandBufferState state);
 };