Enable ASSERT when DCHECK_ALWAYS_ON is defined.

Source/testing/testing.gyp

 #
 # Copyright (C) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #         * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #         * Redistributions in binary form must reproduce the above
@@ skipping 23 matching lines @@
         'source_dir': '../../Source',
         'conditions': [
             ['OS=="linux"', {
                 'use_custom_freetype%': 1,
             }, {
                 'use_custom_freetype%': 0,
             }],
         ],
     },
     'includes': [
+        '../../Source/build/defines_from_chromium.gypi',
         '../../Source/build/features.gypi',
         '../../Source/testing/runner/runner.gypi',
         '../../Source/testing/plugin/plugin.gypi',
     ],
     'targets': [
         {
             'target_name': 'TestRunner',
             'type': '<(component)',
             'defines': [
                 'WEBTESTRUNNER_IMPLEMENTATION=1',
@@ skipping 248 matching lines @@
                 'cflags_cc': ['-Wno-c++0x-compat'],
             },
         }],
         ['clang==1', {
             'target_defaults': {
                 # FIXME: Add -Wglobal-constructors after fixing existing bugs.
             },
         }],
     ], # conditions
 }