Always use ChannelMojo for content child processes.

content/common/in_process_child_thread_params.h

 // 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.
 
 #ifndef CONTENT_COMMON_IN_PROCESS_CHILD_THREAD_PARAMS_H_
 #define CONTENT_COMMON_IN_PROCESS_CHILD_THREAD_PARAMS_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Tells ChildThreadImpl to run in in-process mode. There are a couple of
 // parameters to run in the mode: An emulated io task runner used by
 // ChnanelMojo, an IPC channel name to open.
 class CONTENT_EXPORT InProcessChildThreadParams {
  public:
-  InProcessChildThreadParams(
-      const std::string& channel_name,
-      scoped_refptr<base::SequencedTaskRunner> io_runner,
-      const std::string& application_token = std::string());
+  InProcessChildThreadParams(scoped_refptr<base::SequencedTaskRunner> io_runner,
+                             const std::string& application_token);
   InProcessChildThreadParams(const InProcessChildThreadParams& other);
   ~InProcessChildThreadParams();
 
-  const std::string& channel_name() const { return channel_name_; }
   scoped_refptr<base::SequencedTaskRunner> io_runner() const {
     return io_runner_;
   }
   const std::string& application_token() const {
     return application_token_;
   }
 
  private:
-  std::string channel_name_;
   scoped_refptr<base::SequencedTaskRunner> io_runner_;
   std::string application_token_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_IN_PROCESS_CHILD_THREAD_PARAMS_H_