Convert mojo::system::ChannelEndpointClient to use our new refcounting stuff (instead of base's).

mojo/edk/system/channel_endpoint.h

 // 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.
 
 #ifndef MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_
 #define MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_
 
 #include <memory>
 
-#include "base/memory/ref_counted.h"
 #include "mojo/edk/system/channel_endpoint_id.h"
 #include "mojo/edk/system/message_in_transit_queue.h"
 #include "mojo/edk/system/mutex.h"
 #include "mojo/edk/system/ref_counted.h"
+#include "mojo/edk/system/ref_ptr.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
 namespace system {
 
 class Channel;
 class ChannelEndpointClient;
 class MessageInTransit;
 
 // TODO(vtl): The plan:
@@ skipping 95 matching lines @@
   // called.)
   bool EnqueueMessage(std::unique_ptr<MessageInTransit> message);
 
   // Called to *replace* current client with a new client (which must differ
   // from the existing client). This must not be called after
   // |DetachFromClient()| has been called.
   //
   // This returns true in the typical case, and false if this endpoint has been
   // detached from the channel, in which case the caller should probably call
   // its (new) client's |OnDetachFromChannel()|.
-  bool ReplaceClient(ChannelEndpointClient* client, unsigned client_port);
+  bool ReplaceClient(RefPtr<ChannelEndpointClient>&& client,
+                     unsigned client_port);
 
   // Called before the |ChannelEndpointClient| gives up its reference to this
   // object.
   void DetachFromClient();
 
   // Methods called by |Channel|:
 
   // Called when the |Channel| takes a reference to this object. This will send
   // all queue messages (in |channel_message_queue_|).
   // TODO(vtl): Maybe rename this "OnAttach"?
@@ skipping 12 matching lines @@
   FRIEND_MAKE_REF_COUNTED(ChannelEndpoint);
 
   // Constructor for a |ChannelEndpoint| with the given client (specified by
   // |client| and |client_port|). Optionally takes messages from
   // |*message_queue| if |message_queue| is non-null.
   //
   // |client| may be null if this endpoint will never need to receive messages,
   // in which case |message_queue| should not be null. In that case, this
   // endpoint will simply send queued messages upon being attached to a
   // |Channel| and immediately detach itself.
-  ChannelEndpoint(ChannelEndpointClient* client,
+  ChannelEndpoint(RefPtr<ChannelEndpointClient>&& client,
                   unsigned client_port,
                   MessageInTransitQueue* message_queue = nullptr);
 
-  friend class base::RefCountedThreadSafe<ChannelEndpoint>;
   ~ChannelEndpoint();
 
   bool WriteMessageNoLock(std::unique_ptr<MessageInTransit> message)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Helper for |OnReadMessage()|, handling messages for the client.
   void OnReadMessageForClient(std::unique_ptr<MessageInTransit> message);
 
   // Moves |state_| from |RUNNING| to |DEAD|. |channel_| must be non-null, but
   // this does not call |channel_->DetachEndpoint()|.
   void DieNoLock() MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   Mutex mutex_;
 
   enum class State {
     // |AttachAndRun()| has not been called yet (|channel_| is null).
     PAUSED,
     // |AttachAndRun()| has been called, but not |DetachFromChannel()|
     // (|channel_| is non-null and valid).
     RUNNING,
     // |DetachFromChannel()| has been called (|channel_| is null).
     DEAD
   };
   State state_ MOJO_GUARDED_BY(mutex_);
 
   // |client_| must be valid whenever it is non-null. Before |*client_| gives up
   // its reference to this object, it must call |DetachFromClient()|.
-  // NOTE: This is a |scoped_refptr<>|, rather than a raw pointer, since the
-  // |Channel| needs to keep the |MessagePipe| alive for the "proxy-proxy" case.
-  // Possibly we'll be able to eliminate that case when we have full
-  // multiprocess support.
+  // NOTE: This is a |RefPtr<>|, rather than a raw pointer, since the |Channel|
+  // needs to keep the client (e.g., |MessagePipe|) alive for the "proxy-proxy"
+  // case.
   // WARNING: |ChannelEndpointClient| methods must not be called under |mutex_|.
   // Thus to make such a call, a reference must first be taken under |mutex_|
   // and the lock released.
   // TODO(vtl): Annotate the above rule using |MOJO_ACQUIRED_{BEFORE,AFTER}()|,
   // once clang actually checks such annotations.
   // https://github.com/domokit/mojo/issues/313
   // WARNING: Beware of interactions with |ReplaceClient()|. By the time the
   // call is made, the client may have changed. This must be detected and dealt
   // with.
-  scoped_refptr<ChannelEndpointClient> client_ MOJO_GUARDED_BY(mutex_);
+  RefPtr<ChannelEndpointClient> client_ MOJO_GUARDED_BY(mutex_);
   unsigned client_port_ MOJO_GUARDED_BY(mutex_);
 
   // |channel_| must be valid whenever it is non-null. Before |*channel_| gives
   // up its reference to this object, it must call |DetachFromChannel()|.
   // |local_id_| and |remote_id_| are valid if and only |channel_| is non-null.
   Channel* channel_ MOJO_GUARDED_BY(mutex_);
   ChannelEndpointId local_id_ MOJO_GUARDED_BY(mutex_);
   ChannelEndpointId remote_id_ MOJO_GUARDED_BY(mutex_);
 
   // This queue is used before we're running on a channel and ready to send
   // messages to the channel.
   MessageInTransitQueue channel_message_queue_ MOJO_GUARDED_BY(mutex_);
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(ChannelEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_