TaskScheduler: Remove base::ExecutionMode.

base/BUILD.gn

 # Copyright (c) 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.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 1923 matching lines @@
     "task_scheduler/scheduler_worker_stack_unittest.cc",
     "task_scheduler/scheduler_worker_unittest.cc",
     "task_scheduler/sequence_sort_key_unittest.cc",
     "task_scheduler/sequence_unittest.cc",
     "task_scheduler/task_scheduler_impl_unittest.cc",
     "task_scheduler/task_tracker_posix_unittest.cc",
     "task_scheduler/task_tracker_unittest.cc",
     "task_scheduler/task_unittest.cc",
     "task_scheduler/test_task_factory.cc",
     "task_scheduler/test_task_factory.h",
+    "task_scheduler/test_utils.h",
     "template_util_unittest.cc",
     "test/histogram_tester_unittest.cc",
     "test/test_pending_task_unittest.cc",
     "test/test_reg_util_win_unittest.cc",
     "test/trace_event_analyzer_unittest.cc",
     "test/user_action_tester_unittest.cc",
     "threading/non_thread_safe_unittest.cc",
     "threading/platform_thread_unittest.cc",
     "threading/post_task_and_reply_impl_unittest.cc",
     "threading/sequenced_task_runner_handle_unittest.cc",
@@ skipping 499 matching lines @@
     testonly = true
     deps = [
       ":base_java",
     ]
     java_files = [
       "test/android/java/src/org/chromium/base/ContentUriTestUtils.java",
       "test/android/java/src/org/chromium/base/TestSystemMessageHandler.java",
     ]
   }
 }