Allow any Chromium trybot to run webkit_tests.

scripts/slave/recipes/chromium_trybot.py

 # Copyright 2013 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.
 
 import collections
 
 from recipe_engine.types import freeze
 
 DEPS = [
   'depot_tools/bot_update',
@@ skipping 129 matching lines @@
     subproject_tag = 'blink'
   elif affects_blink_paths:
     subproject_tag = 'blink-paths'
   else:
     subproject_tag = 'chromium'
   api.tryserver.set_subproject_tag(subproject_tag)
 
   # TODO(phajdan.jr): Remove special case for layout tests.
   add_blink_tests = (affects_blink_paths and
                      buildername in CHROMIUM_BLINK_TESTS_BUILDERS)
+  add_blink_tests = api.properties.get('force_blink_tests', add_blink_tests)
 
   # Add blink tests that work well with "analyze" here. The tricky ones
   # that bypass it (like the layout tests) are added later.
   if add_blink_tests:
     add_tests([
         api.chromium_tests.steps.GTestTest('blink_heap_unittests'),
         api.chromium_tests.steps.GTestTest('blink_platform_unittests'),
         api.chromium_tests.steps.GTestTest('webkit_unit_tests'),
         api.chromium_tests.steps.GTestTest('wtf_unittests'),
     ])
@@ skipping 749 matching lines @@
     props(mastername='tryserver.v8',
           buildername='v8_linux_blink_rel',
           patch_project='v8') +
     api.platform.name('linux') +
     suppress_analyze(more_exclusions=['v8/f.*']) +
     api.override_step_data('webkit_tests (with patch)',
         api.test_utils.canned_test_output(passing=False)) +
     api.override_step_data('webkit_tests (without patch)',
         api.test_utils.canned_test_output(passing=True, minimal=True))
   )