Move IPC fuzzer switches and helpers from chrome/common to content/common.

chrome/common/external_ipc_dumper.h

Index: chrome/common/external_ipc_dumper.h
diff --git a/chrome/common/external_ipc_dumper.h b/chrome/common/external_ipc_dumper.h
deleted file mode 100644
index fd6f6a2ee353571e1ecf557bfaef796b3f914f2a..0000000000000000000000000000000000000000
--- a/chrome/common/external_ipc_dumper.h
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) 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 CHROME_COMMON_EXTERNAL_IPC_DUMPER_H_
-#define CHROME_COMMON_EXTERNAL_IPC_DUMPER_H_
-
-#include "ipc/ipc_channel_proxy.h"
-
-IPC::ChannelProxy::OutgoingMessageFilter* LoadExternalIPCDumper(
-    const base::FilePath& dump_directory);
-
-#endif  // CHROME_COMMON_EXTERNAL_IPC_DUMPER_H_