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

gpu/ipc/service/gpu_command_buffer_stub.h

Index: gpu/ipc/service/gpu_command_buffer_stub.h
diff --git a/gpu/ipc/service/gpu_command_buffer_stub.h b/gpu/ipc/service/gpu_command_buffer_stub.h
index bf40d4f691792e47dc0f3aba6bb65dc8e311db30..b33c6462e258fa6e39572b48659efc88de2db3a1 100644
--- a/gpu/ipc/service/gpu_command_buffer_stub.h
+++ b/gpu/ipc/service/gpu_command_buffer_stub.h
@@ -160,7 +160,9 @@ class GPU_EXPORT GpuCommandBufferStub
   void OnInitialize(base::SharedMemoryHandle shared_state_shm,
                     IPC::Message* reply_message);
   void OnSetGetBuffer(int32_t shm_id, IPC::Message* reply_message);
-  void OnProduceFrontBuffer(const Mailbox& mailbox);
+  void OnTakeFrontBuffer(const Mailbox& mailbox);
+  void OnReturnFrontBuffer(const Mailbox& mailbox,
+                           bool is_lost);
   void OnGetState(IPC::Message* reply_message);
   void OnWaitForTokenInRange(int32_t start,
                              int32_t end,
@@ -179,6 +181,7 @@ class GPU_EXPORT GpuCommandBufferStub
 
   void OnEnsureBackbuffer();
 
+  void OnWaitSyncToken(const SyncToken& sync_token);
   void OnSignalSyncToken(const SyncToken& sync_token, uint32_t id);
   void OnSignalAck(uint32_t id);
   void OnSignalQuery(uint32_t query, uint32_t id);