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diff --git a/content/common/child_process_host.h b/content/common/child_process_host.h
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+// 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 CONTENT_COMMON_CHILD_PROCESS_HOST_H_
+#define CONTENT_COMMON_CHILD_PROCESS_HOST_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif  // defined(OS_WIN)
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "content/common/notification_type.h"
+#include "ipc/ipc_channel_proxy.h"
+
+class CommandLine;
+class FilePath;
+
+namespace IPC {
+class Message;
+}
+
+// Provides common functionality for hosting a child process and processing IPC
+// messages between the host and the child process. Subclasses are responsible
+// for the actual launching and terminating of the child processes.
+class ChildProcessHost : public IPC::Channel::Listener,
+                         public IPC::Message::Sender {
+ public:
+  virtual ~ChildProcessHost();
+
+  // Returns the pathname to be used for a child process.  If a subprocess
+  // pathname was specified on the command line, that will be used.  Otherwise,
+  // the default child process pathname will be returned.  On most platforms,
+  // this will be the same as the currently-executing process.
+  //
+  // The argument allow_self is used on Linux to indicate that we allow us to
+  // fork from /proc/self/exe rather than using the "real" app path. This
+  // prevents autoupdate from confusing us if it changes the file out from
+  // under us. You will generally want to set this to true, except when there
+  // is an override to the command line (for example, we're forking a renderer
+  // in gdb). In this case, you'd use GetChildPath to get the real executable
+  // file name, and then prepend the GDB command to the command line.
+  //
+  // On failure, returns an empty FilePath.
+  static FilePath GetChildPath(bool allow_self);
+
+#if defined(OS_WIN)
+  // See comments in the cc file. This is a common hack needed for a process
+  // hosting a sandboxed child process. Hence it lives in this file.
+  static void PreCacheFont(LOGFONT font);
+#endif  // defined(OS_WIN)
+
+  // IPC::Message::Sender implementation.
+  virtual bool Send(IPC::Message* message);
+
+ protected:
+  ChildProcessHost();
+
+  // Adds an IPC message filter.  A reference will be kept to the filter.
+  void AddFilter(IPC::ChannelProxy::MessageFilter* filter);
+
+  // Derived classes return true if it's ok to shut down the child process.
+  virtual bool CanShutdown() = 0;
+
+  // Send the shutdown message to the child process.
+  // Does not check if CanShutdown is true.
+  virtual void ForceShutdown();
+
+  // Creates the IPC channel.  Returns true iff it succeeded.
+  virtual bool CreateChannel();
+
+  // Notifies us that an instance has been created on this child process.
+  virtual void InstanceCreated();
+
+  // IPC::Channel::Listener implementation:
+  virtual bool OnMessageReceived(const IPC::Message& msg);
+  virtual void OnChannelConnected(int32 peer_pid);
+  virtual void OnChannelError();
+
+  bool opening_channel() { return opening_channel_; }
+  const std::string& channel_id() { return channel_id_; }
+  IPC::Channel* channel() { return channel_.get(); }
+
+  // Called when the child process goes away.
+  virtual void OnChildDied();
+  // Notifies the derived class that we told the child process to kill itself.
+  virtual void ShutdownStarted();
+  // Subclasses can implement specific notification methods.
+  virtual void Notify(NotificationType type);
+
+ 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:
+    explicit ListenerHook(ChildProcessHost* host);
+    virtual bool OnMessageReceived(const IPC::Message& msg);
+    virtual void OnChannelConnected(int32 peer_pid);
+    virtual void OnChannelError();
+   private:
+    ChildProcessHost* host_;
+  };
+
+  ListenerHook listener_;
+
+  bool opening_channel_;  // True while we're waiting the channel to be opened.
+  scoped_ptr<IPC::Channel> channel_;
+  std::string channel_id_;
+
+  // Holds all the IPC message filters.  Since this object lives on the IO
+  // thread, we don't have a IPC::ChannelProxy and so we manage filters
+  // manually.
+  std::vector<scoped_refptr<IPC::ChannelProxy::MessageFilter> > filters_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
+};
+
+#endif  // CONTENT_COMMON_CHILD_PROCESS_HOST_H_