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

ppapi/proxy/callback_tracker.cc

-// 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.
-
-#include "ppapi/proxy/callback_tracker.h"
-
-#include "ppapi/proxy/dispatcher.h"
-#include "ppapi/proxy/ppapi_messages.h"
-
-namespace ppapi {
-namespace proxy {
-
-namespace {
-
-struct CallbackData {
-  CallbackTracker* tracker;
-  uint32_t callback_id;
-};
-
-void CallbackProxy(void* user_data, int32_t result) {
-  CallbackData* data = static_cast<CallbackData*>(user_data);
-  data->tracker->SendExecuteSerializedCallback(data->callback_id, result);
-  delete data;
-}
-
-}  // namespace
-
-CallbackTracker::CallbackTracker(Dispatcher* dispatcher)
-    : dispatcher_(dispatcher),
-      next_callback_id_(1) {
-}
-
-CallbackTracker::~CallbackTracker() {
-}
-
-uint32_t CallbackTracker::SendCallback(PP_CompletionCallback callback) {
-  // Find the next callback ID we can use (being careful about wraparound).
-  while (callback_map_.find(next_callback_id_) != callback_map_.end())
-    next_callback_id_++;
-  callback_map_[next_callback_id_] = callback;
-  return next_callback_id_++;
-}
-
-PP_CompletionCallback CallbackTracker::ReceiveCallback(
-    uint32_t serialized_callback) {
-  CallbackData* data = new CallbackData;
-  data->tracker = this;
-  data->callback_id = serialized_callback;
-  return PP_MakeCompletionCallback(&CallbackProxy, data);
-}
-
-void CallbackTracker::SendExecuteSerializedCallback(
-    uint32_t serialized_callback,
-    int32_t param) {
-  dispatcher_->Send(new PpapiMsg_ExecuteCallback(serialized_callback, param));
-}
-
-void CallbackTracker::ReceiveExecuteSerializedCallback(
-    uint32_t serialized_callback,
-    int32_t param) {
-  CallbackMap::iterator found = callback_map_.find(serialized_callback);
-  if (found == callback_map_.end()) {
-    NOTREACHED();
-    return;
-  }
-
-  PP_RunCompletionCallback(&found->second, param);
-  callback_map_.erase(found);
-}
-
-}  // namespace proxy
-}  // namespace ppapi