Delete UDPClientSocket on same thread as creation. Also refactor.

chrome/browser/extensions/api/socket/socket_api_controller.h

 // Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_API_SOCKET_SOCKET_API_CONTROLLER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_SOCKET_SOCKET_API_CONTROLLER_H_
 #pragma once
 
 #include <string>
 #include <map>
 
+#include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/singleton.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/completion_callback.h"
 
 class Profile;
 
 namespace base {
 class ListValue;
 class Value;
 }
 
 namespace net {
 class UDPClientSocket;
 class IPEndPoint;
 }
 
 namespace extensions {
 
 class Socket;
 
-// The SocketController singleton keeps track of all our Sockets, and provides
-// a convenient set of methods to manipulate them.
+// SocketController keeps track of a collection of Sockets and provides a
+// convenient set of methods to manipulate them.
 class SocketController {
  public:
-  static SocketController* GetInstance();
-
   SocketController();
   virtual ~SocketController();
 
   // Create/Destroy are a pair. They represent the allocation and deallocation
   // of the Socket object in memory.
   //
-  // TODO(miket): we currently require the app developer to remember to call
-  // Destroy, which is a buzzkill in JavaScript. I believe that to solve this,
-  // we'll have to associate each Socket with a creator extension, and then
-  // clean up when the extension goes out of scope. As the API is defined
-  // today, we're exposing only primitive socketIds to JavaScript, which seems
-  // to imply that we won't be able to garbage-collect when individual sockets
-  // "go out of scope" (in quotes because they never do).
+  // TODO(miket): aa's suggestion to track lifetime of callbacks associated
+  // with each socket, which will then let us clean up when we go out of scope
+  // rather than requiring that the app developer remember to call Destroy.
   int CreateUdp(const Profile* profile, const std::string& extension_id,
                 const GURL& src_url);
   bool DestroyUdp(int socket_id);
 
   // Connect, Close, Read, and Write map to the equivalent methods in
   // UDPClientSocket.
   //
   // TODO(miket): Implement Read.
   bool ConnectUdp(int socket_id, const std::string address, int port);
   void CloseUdp(int socket_id);
   int WriteUdp(int socket_id, const std::string msg);
 
   // Converts a string IP address and integer port into a format that
   // UDPClientSocket can deal with. Public so test harness can use it.
   static bool CreateIPEndPoint(const std::string address, int port,
                                net::IPEndPoint* ip_end_point);
 
  private:
   int next_socket_id_;
-  typedef std::map<int, Socket*> SocketMap;
+  typedef std::map<int, linked_ptr<Socket> > SocketMap;
   SocketMap socket_map_;
 
   // Convenience method for accessing SocketMap.
   Socket* GetSocket(int socket_id);
 
-  friend struct DefaultSingletonTraits<SocketController>;
-
   DISALLOW_COPY_AND_ASSIGN(SocketController);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_SOCKET_SOCKET_API_CONTROLLER_H_