Revert 106717 - Revert 106677 (caused several PPAPI test timeouts, see http://crbug.com/101154)

ppapi/proxy/callback_tracker.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 PPAPI_PROXY_CALLBACK_TRACKER_H_
-#define PPAPI_PROXY_CALLBACK_TRACKER_H_
-
-#include <map>
-
-#include "ppapi/c/pp_completion_callback.h"
-#include "ppapi/c/pp_stdint.h"
-
-namespace ppapi {
-namespace proxy {
-
-class Dispatcher;
-
-// This object tracks cross-process callbacks. When the plugin sends a callback
-// object to the renderer, we save the information and pass an identifier
-// instead.
-//
-// On the renderer side, this identifier is converted to a new callback in that
-// process. When executed, this new callback sends an IPC message containing the
-// previous identifier back to the plugin.
-//
-// When we receive that message, ExecuteSerializedCallback converts the
-// identifier back to the original callback information and runs the callback.
-class CallbackTracker {
- public:
-  CallbackTracker(Dispatcher* dispatcher);
-  ~CallbackTracker();
-
-  // Converts the given callback in the context of the plugin to a serialized
-  // ID. This will be passed to ReceiveCallback on the renderer side.
-  uint32_t SendCallback(PP_CompletionCallback callback);
-
-  // Converts the given serialized callback ID to a new completion callback in
-  // the context of the current process. This callback actually will represent
-  // a proxy that will execute the callback in the plugin process.
-  PP_CompletionCallback ReceiveCallback(uint32_t serialized_callback);
-
-  // Sends a request to the remote process to execute the given callback.
-  void SendExecuteSerializedCallback(uint32_t serialized_callback,
-                                     int32_t param);
-
-  // Executes the given callback ID with the given result in the current
-  // process. This will also destroy the information associated with the
-  // callback and the serialized ID won't be valid any more.
-  void ReceiveExecuteSerializedCallback(uint32_t serialized_callback,
-                                        int32_t param);
-
- private:
-  // Pointer to the dispatcher that owns us.
-  Dispatcher* dispatcher_;
-
-  int32_t next_callback_id_;
-
-  // Maps callback IDs to the actual callback objects in the plugin process.
-  typedef std::map<int32_t, PP_CompletionCallback> CallbackMap;
-  CallbackMap callback_map_;
-};
-
-}  // namespace proxy
-}  // namespace ppapi
-
-#endif  // PPAPI_PROXY_CALLBACK_TRACKER_H_