Always use ChannelMojo for content child processes.

tools/ipc_fuzzer/fuzzer/fuzzer.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 <iostream>
 #include <set>
 #include <string>
 #include <tuple>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/shared_memory_handle.h"
 #include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_utils.h"
-#include "ipc/ipc_switches.h"
 #include "ipc/ipc_sync_channel.h"
 #include "ipc/ipc_sync_message.h"
 #include "tools/ipc_fuzzer/fuzzer/fuzzer.h"
 #include "tools/ipc_fuzzer/fuzzer/rand_util.h"
 #include "tools/ipc_fuzzer/message_lib/message_cracker.h"
 #include "tools/ipc_fuzzer/message_lib/message_file.h"
 
 #if defined(OS_POSIX)
 #include <unistd.h>
 #endif
@@ skipping 1996 matching lines @@
 #include "tools/ipc_fuzzer/message_lib/all_message_null_macros.h"
 #undef IPC_MESSAGE_DECL
 #define IPC_MESSAGE_DECL(name, ...) \
   (*map)[static_cast<uint32_t>(name::ID)] = FuzzerHelper<name>::Fuzz;
 
 void PopulateFuzzerFunctionMap(FuzzerFunctionMap* map) {
 #include "tools/ipc_fuzzer/message_lib/all_messages.h"
 }
 
 }  // namespace ipc_fuzzer