Mark memory_watcher as chromium_code.

tools/memory_watcher/memory_watcher.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,
+  },
   'targets': [
     {
       'target_name': 'memory_watcher',
       'type': 'shared_library',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../ui/gfx/gfx.gyp:gfx',
         '../../ui/ui.gyp:ui',
       ],
       'defines': [
@@ skipping 19 matching lines @@
         'memory_watcher.cc',
         'memory_watcher.h',
         'mini_disassembler.cc',
         'preamble_patcher.cc',
         'preamble_patcher.h',
         'preamble_patcher_with_stub.cc',
       ],
     },
   ],
 }