Combine traits for IPC mutation and generation fuzzing plus other refactoring.

tools/ipc_fuzzer/ipc_fuzzer.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
       'target_name': 'ipc_fuzzer',
       'type': 'none',
       'dependencies': [
         'dump/dump.gyp:ipc_message_dump',
         'ipclist/ipclist.gyp:ipclist',
+        'mutate/mutate.gyp:ipc_fuzzer_generate',
         'mutate/mutate.gyp:ipc_fuzzer_mutate',
-        'mutate/mutate.gyp:ipc_fuzzer_generate',
         'mutate/mutate.gyp:ipc_message_util',
         'replay/replay.gyp:ipc_fuzzer_replay',
       ],
     },
   ],
 }