IPC fuzzer child process component

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index e1845fce70f1e87d72245536f86adad7b2cdc655..8cd9c2ac5952cf2f208bbf943ae48790633bb508 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -791,6 +791,9 @@
       'google_api_key%': '',
       'google_default_client_id%': '',
       'google_default_client_secret%': '',
+
+      # IPC fuzzer is disabled by default.
+      'enable_ipc_fuzzer%': 0,
     },
 
     # Copy conditionally-set variables out one scope.
@@ -1154,6 +1157,8 @@
     # Use the chromium skia by default.
     'use_system_skia%': '0',
 
+    'enable_ipc_fuzzer%': '<(enable_ipc_fuzzer)',
+
     'conditions': [
       # The version of GCC in use, set later in platforms that use GCC and have
       # not explicitly chosen to build with clang. Currently, this means all
@@ -2336,7 +2341,10 @@
       }],
       ['enable_mdns==1', {
         'defines': ['ENABLE_MDNS=1'],
-      }]
+      }],
+      ['enable_ipc_fuzzer==1', {
+        'defines': ['ENABLE_IPC_FUZZER=1'],
+      }],
     ],  # conditions for 'target_defaults'
     'target_conditions': [
       ['enable_wexit_time_destructors==1', {