Mojo: Move PlatformChannelPair to its own files.

mojo/system/platform_channel.h

 // Copyright 2013 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 MOJO_SYSTEM_PLATFORM_CHANNEL_H_
 #define MOJO_SYSTEM_PLATFORM_CHANNEL_H_
 
-#include "base/basictypes.h"
+#include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/process/launch.h"
 #include "mojo/system/platform_channel_handle.h"
 #include "mojo/system/system_impl_export.h"
 
-class CommandLine;
-
 namespace mojo {
 namespace system {
 
 class MOJO_SYSTEM_IMPL_EXPORT PlatformChannel {
  public:
   virtual ~PlatformChannel();
 
   // Creates a channel if you already have the underlying handle for it, taking
   // ownership of |handle|.
   static scoped_ptr<PlatformChannel> CreateFromHandle(
       const PlatformChannelHandle& handle);
 
   // Returns the channel's handle, passing ownership.
   PlatformChannelHandle PassHandle();
 
   bool is_valid() const { return handle_.is_valid(); }
 
  protected:
   PlatformChannel();
 
   PlatformChannelHandle* mutable_handle() { return &handle_; }
 
  private:
   PlatformChannelHandle handle_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformChannel);
 };
 
-// This is used to create a pair of connected |PlatformChannel|s. The resulting
-// channels can then be used in the same process (e.g., in tests) or between
-// processes. (The "server" channel is the one that will be used in the process
-// that created the pair, whereas the "client" channel is the one that will be
-// used in a different process.)
-//
-// This class provides facilities for passing the client channel to a child
-// process. The parent should call |PrepareToPassClientChannelToChildProcess()|
-// to get the data needed to do this, spawn the child using that data, and then
-// call |ChildProcessLaunched()|. Note that on Windows this facility (will) only
-// work on Vista and later (TODO(vtl)).
-//
-// Note: |PlatformChannelPair()|, |CreateClientChannelFromParentProcess()|,
-// |PrepareToPassClientChannelToChildProcess()|, and |ChildProcessLaunched()|
-// have platform-specific implementations.
-class MOJO_SYSTEM_IMPL_EXPORT PlatformChannelPair {
- public:
-  PlatformChannelPair();
-  ~PlatformChannelPair();
-
-  // This transfers ownership of the server channel to the caller. Returns null
-  // on failure.
-  scoped_ptr<PlatformChannel> CreateServerChannel();
-
-  // For in-process use (e.g., in tests). This transfers ownership of the client
-  // channel to the caller. Returns null on failure.
-  scoped_ptr<PlatformChannel> CreateClientChannel();
-
-  // To be called in the child process, after the parent process called
-  // |PrepareToPassClientChannelToChildProcess()| and launched the child (using
-  // the provided data), to create a client channel connected to the server
-  // channel (in the parent process). Returns null on failure.
-  static scoped_ptr<PlatformChannel> CreateClientChannelFromParentProcess(
-      const CommandLine& command_line);
-
-  // Prepares to pass the client channel to a new child process, to be launched
-  // using |LaunchProcess()| (from base/launch.h). Modifies |*command_line| and
-  // |*file_handle_mapping| as needed. (|file_handle_mapping| may be null on
-  // platforms that don't need it, like Windows.)
-  void PrepareToPassClientChannelToChildProcess(
-      CommandLine* command_line,
-      base::FileHandleMappingVector* file_handle_mapping) const;
-  // To be called once the child process has been successfully launched, to do
-  // any cleanup necessary.
-  void ChildProcessLaunched();
-
- private:
-  PlatformChannelHandle server_handle_;
-  PlatformChannelHandle client_handle_;
-
-  DISALLOW_COPY_AND_ASSIGN(PlatformChannelPair);
-};
-
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_PLATFORM_CHANNEL_H_