ipc: Create AttachmentBrokerPrivileged and AttachmentBrokerUnprivileged.

ipc/attachment_broker_privileged.cc

+// Copyright 2015 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 "ipc/attachment_broker_privileged.h"
+
+#include <algorithm>
+
+#include "ipc/ipc_channel.h"
+
+namespace IPC {
+
+AttachmentBrokerPrivileged::AttachmentBrokerPrivileged() {}
+
+AttachmentBrokerPrivileged::~AttachmentBrokerPrivileged() {}
+
+void AttachmentBrokerPrivileged::RegisterCommunicationChannel(
+    Channel* channel) {
+  auto it = std::find(channels_.begin(), channels_.end(), channel);
+  DCHECK(channels_.end() == it);
+  channels_.push_back(channel);
+}
+
+void AttachmentBrokerPrivileged::DeregisterCommunicationChannel(
+    Channel* channel) {
+  auto it = std::find(channels_.begin(), channels_.end(), channel);
+  if (it != channels_.end())
+    channels_.erase(it);
+}
+
+Channel* AttachmentBrokerPrivileged::GetChannelWithProcessId(
+    base::ProcessId id) {
+  auto it = std::find_if(channels_.begin(), channels_.end(),
+                         [id](Channel* c) { return c->GetPeerPID() == id; });
+  if (it == channels_.end())
+    return nullptr;
+  return *it;
+}
+
+}  // namespace IPC