Example of how to interpose yourself in a message stream.

chrome/chrome.gyp

 # Copyright (c) 2011 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,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 819 matching lines @@
             'service/remoting/chromoting_host_manager.cc',
             'service/remoting/chromoting_host_manager.h',
           ],
         }],
       ],
     },
     {
       'target_name': 'ipclist',
       'type': 'executable',
       'dependencies': [
-         'chrome',
-         'chrome_resources',
-         'chrome_strings',
-         'test_support_common',
-         'test_support_ui',
-         '../skia/skia.gyp:skia',
-         '../testing/gtest.gyp:gtest',
-         '../third_party/libxslt/libxslt.gyp:libxslt',
-         '../third_party/npapi/npapi.gyp:npapi',
+        'test_support_common',
+        '../skia/skia.gyp:skia',
       ],
       'include_dirs': [
          '..',
       ],
       'sources': [
         'tools/ipclist/all_messages.h',
         'tools/ipclist/ipclist.cc',
       ],
     },
   ],
@@ skipping 395 matching lines @@
                              '<@(_inputs)'],
                   'message': 'Stripping reliability tests',
                 },
               ],
               'dependencies': [
                 'automated_ui_tests',
                 'reliability_tests',
               ],
             }],
           ],
-        }
+        },
+        {
+          'target_name': 'ipcfuzz',
+          'type': 'loadable_module',
+          'include_dirs': [
+            '..',
+          ],
+          'dependencies': [
+            'test_support_common',
+            '../skia/skia.gyp:skia',
+          ],
+          'sources': [
+            'tools/ipclist/all_messages.h',
+            'tools/ipclist/ipcfuzz.cc',
+          ],
+        },
       ],
     },],  # OS=="linux"
     ['OS=="win"',
       { 'targets': [
         {
           # TODO(sgk):  remove this when we change the buildbots to
           # use the generated build\all.sln file to build the world.
           'target_name': 'pull_in_all',
           'type': 'none',
           'dependencies': [
@@ skipping 318 matching lines @@
       }],  # targets
     }],  # OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"
   ],  # 'conditions'
 }
 
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