Give AwakableList's wake-up method the old state in addition to the new state.

mojo/edk/system/data_pipe.h

 // Copyright 2013 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.
 
 #ifndef MOJO_EDK_SYSTEM_DATA_PIPE_H_
 #define MOJO_EDK_SYSTEM_DATA_PIPE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 257 matching lines @@
   DataPipe(bool has_local_producer,
            bool has_local_consumer,
            const MojoCreateDataPipeOptions& validated_options,
            std::unique_ptr<DataPipeImpl> impl);
   ~DataPipe() override;
 
   // |ChannelEndpointClient| implementation:
   bool OnReadMessage(unsigned port, MessageInTransit* message) override;
   void OnDetachFromChannel(unsigned port) override;
 
-  void AwakeProducerAwakablesForStateChangeNoLock(
-      const HandleSignalsState& new_producer_state)
+  void OnProducerMaybeStateChange(const HandleSignalsState& old_producer_state,
+                                  const HandleSignalsState& new_producer_state)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
-  void AwakeConsumerAwakablesForStateChangeNoLock(
-      const HandleSignalsState& new_consumer_state)
+  void OnConsumerMaybeStateChange(const HandleSignalsState& old_consumer_state,
+                                  const HandleSignalsState& new_consumer_state)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   void SetProducerClosed();
   void SetConsumerClosed();
 
   bool has_local_producer_no_lock() const MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
     mutex_.AssertHeld();
     return !!producer_awakable_list_;
   }
   bool has_local_consumer_no_lock() const MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
@@ skipping 20 matching lines @@
   uint32_t consumer_two_phase_max_num_bytes_read_ MOJO_GUARDED_BY(mutex_);
   std::unique_ptr<DataPipeImpl> impl_ MOJO_GUARDED_BY(mutex_);
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipe);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_DATA_PIPE_H_