Example of how to interpose yourself in a message stream.

chrome/chrome.gyp

Index: chrome/chrome.gyp
===================================================================
--- chrome/chrome.gyp	(revision 83227)
+++ chrome/chrome.gyp	(working copy)
@@ -849,15 +849,8 @@
       'target_name': 'ipclist',
       'type': 'executable',
       'dependencies': [
-         'chrome',
-         'chrome_resources',
-         'chrome_strings',
-         'test_support_common',
-         'test_support_ui',
+          'test_support_common',

[jam, 2011/04/28 23:43:46]

nit: spacing is off

          '../skia/skia.gyp:skia',
-         '../testing/gtest.gyp:gtest',
-         '../third_party/libxslt/libxslt.gyp:libxslt',
-         '../third_party/npapi/npapi.gyp:npapi',
       ],
       'include_dirs': [
          '..',
@@ -867,6 +860,21 @@
         'tools/ipclist/ipclist.cc',
       ],
     },
+    {
+      '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',
+      ],
+    },
   ],
   'conditions': [
     ['OS=="mac"',