diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/chrome/common/child_process_host.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/chrome/common/child_process_host.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,130 @@
+// Copyright (c) 2009 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_COMMON_CHILD_PROCESS_HOST_H_
+#define CHROME_COMMON_CHILD_PROCESS_HOST_H_
+
+#include "build/build_config.h"
+
+#include <list>
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "base/waitable_event_watcher.h"
+#include "chrome/common/child_process_info.h"
+#include "chrome/common/ipc_channel.h"
+
+namespace mozilla {
+namespace ipc {
+class FileDescriptor;
+}
+}
+
+class NotificationType;
+
+// Plugins/workers and other child processes that live on the IO thread should
+// derive from this class.
+class ChildProcessHost :
+                         public IPC::Message::Sender,
+                         public ChildProcessInfo,
+                         public base::WaitableEventWatcher::Delegate,
+                         public IPC::Channel::Listener {
+ public:
+  virtual ~ChildProcessHost();
+
+  // ResourceDispatcherHost::Receiver implementation:
+  virtual bool Send(IPC::Message* msg);
+
+  // The Iterator class allows iteration through either all child processes, or
+  // ones of a specific type, depending on which constructor is used.  Note that
+  // this should be done from the IO thread and that the iterator should not be
+  // kept around as it may be invalidated on subsequent event processing in the
+  // event loop.
+  class Iterator {
+   public:
+    Iterator();
+    Iterator(ProcessType type);
+    ChildProcessHost* operator->() { return *iterator_; }
+    ChildProcessHost* operator*() { return *iterator_; }
+    ChildProcessHost* operator++();
+    bool Done();
+
+   private:
+    bool all_;
+    ProcessType type_;
+    std::list<ChildProcessHost*>::iterator iterator_;
+  };
+
+ protected:
+  explicit ChildProcessHost(ProcessType type);
+
+  // Derived classes return true if it's ok to shut down the child process.
+  virtual bool CanShutdown() = 0;
+
+  // Creates the IPC channel.  Returns true iff it succeeded.
+  bool CreateChannel();
+
+  bool CreateChannel(mozilla::ipc::FileDescriptor& aFileDescriptor);
+
+  // Once the subclass gets a handle to the process, it needs to tell
+  // ChildProcessHost using this function.
+  void SetHandle(base::ProcessHandle handle);
+
+  // Notifies us that an instance has been created on this child process.
+  void InstanceCreated();
+
+  // IPC::Channel::Listener implementation:
+  virtual void OnMessageReceived(const IPC::Message& msg) { }
+  virtual void OnChannelConnected(int32_t peer_pid) { }
+  virtual void OnChannelError() { }
+
+  bool opening_channel() { return opening_channel_; }
+  const std::wstring& channel_id() { return channel_id_; }
+
+  base::WaitableEvent* GetProcessEvent() { return process_event_.get(); }
+
+  const IPC::Channel& channel() const { return *channel_; }
+  IPC::Channel* channelp() const { return channel_.get(); }
+
+ private:
+  // Sends the given notification to the notification service on the UI thread.
+  void Notify(NotificationType type);
+
+ protected:
+  // WaitableEventWatcher::Delegate implementation:
+  virtual void OnWaitableEventSignaled(base::WaitableEvent *event);
+
+ private:
+  // By using an internal class as the IPC::Channel::Listener, we can intercept
+  // OnMessageReceived/OnChannelConnected and do our own processing before
+  // calling the subclass' implementation.
+  class ListenerHook : public IPC::Channel::Listener {
+   public:
+    ListenerHook(ChildProcessHost* host);
+    virtual void OnMessageReceived(const IPC::Message& msg);
+    virtual void OnChannelConnected(int32_t peer_pid);
+    virtual void OnChannelError();
+    virtual void GetQueuedMessages(std::queue<IPC::Message>& queue);
+   private:
+    ChildProcessHost* host_;
+  };
+
+  ListenerHook listener_;
+
+  // True while we're waiting the channel to be opened.
+  bool opening_channel_;
+
+  // The IPC::Channel.
+  scoped_ptr<IPC::Channel> channel_;
+
+  // IPC Channel's id.
+  std::wstring channel_id_;
+
+  // Used to watch the child process handle.
+  base::WaitableEventWatcher watcher_;
+
+  scoped_ptr<base::WaitableEvent> process_event_;
+};
+
+#endif  // CHROME_COMMON_CHILD_PROCESS_HOST_H_