Introduce TaskRunnerHandle.

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 803 matching lines @@
     "threading/platform_thread_posix.cc",
     "threading/platform_thread_win.cc",
     "threading/post_task_and_reply_impl.cc",
     "threading/post_task_and_reply_impl.h",
     "threading/sequenced_task_runner_handle.cc",
     "threading/sequenced_task_runner_handle.h",
     "threading/sequenced_worker_pool.cc",
     "threading/sequenced_worker_pool.h",
     "threading/simple_thread.cc",
     "threading/simple_thread.h",
+    "threading/task_runner_handle.cc",
+    "threading/task_runner_handle.h",
     "threading/thread.cc",
     "threading/thread.h",
     "threading/thread_checker.h",
     "threading/thread_checker_impl.cc",
     "threading/thread_checker_impl.h",
     "threading/thread_collision_warner.cc",
     "threading/thread_collision_warner.h",
     "threading/thread_id_name_manager.cc",
     "threading/thread_id_name_manager.h",
     "threading/thread_local.h",
@@ skipping 1058 matching lines @@
     "test/icu_test_util.h",
     "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/sequenced_task_runner_handle_unittest.cc",
     "threading/sequenced_worker_pool_unittest.cc",
     "threading/simple_thread_unittest.cc",
+    "threading/task_runner_handle_unittest.cc",
     "threading/thread_checker_unittest.cc",
     "threading/thread_collision_warner_unittest.cc",
     "threading/thread_id_name_manager_unittest.cc",
     "threading/thread_local_storage_unittest.cc",
     "threading/thread_local_unittest.cc",
     "threading/thread_unittest.cc",
     "threading/watchdog_unittest.cc",
     "threading/worker_pool_posix_unittest.cc",
     "threading/worker_pool_unittest.cc",
     "time/pr_time_unittest.cc",
@@ skipping 477 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }