Add an accessibility audit test for WebUI pages

chrome/chrome_tests.gypi

Index: chrome/chrome_tests.gypi
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index c2d28ed3d0667db27e69e0dbc67d21d8ee4c9d8e..ad661199ef50feac5b1993ab0c935538c327a8a1 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1254,6 +1254,7 @@
         'test/base/empty_browser_test.cc',
         'test/base/in_process_browser_test_browsertest.cc',
         'test/base/tracing_browsertest.cc',
+        'test/data/webui/accessibility_audit_browsertest.js',
         'test/data/webui/assertions.js',
         'test/data/webui/async_gen.cc',
         'test/data/webui/async_gen.h',
@@ -1354,7 +1355,7 @@
             }],
             ['OS=="win"', {
               # TODO(halyavin) NaCl on Windows can't open debug stub socket
-              # in browser process as needed by this test. 
+              # in browser process as needed by this test.
               # See http://crbug.com/157312.
               'sources!': [
                 'browser/nacl_host/test/gdb_debug_stub_browsertest.cc',