[Extensions][TaskScheduler] Update ActivityLog for scheduling migration

chrome/browser/extensions/activity_log/activity_log_task_runner.cc

+// Copyright 2017 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.
+
+#include "chrome/browser/extensions/activity_log/activity_log_task_runner.h"
+
+#include "base/sequenced_task_runner.h"
+#include "base/task_scheduler/lazy_task_runner.h"
+
+namespace extensions {
+
+namespace {
+base::TaskRunner* g_task_runner_for_testing = nullptr;
+}
+
+const scoped_refptr<base::TaskRunner> GetActivityLogTaskRunner() {
+  if (g_task_runner_for_testing)
+    return g_task_runner_for_testing;
+
+  static base::LazySequencedTaskRunner task_runner =

[gab, 2017/07/20 16:26:43]

The documentation states to put this in the anonymous namespace, I think it's
probably equivalent as a static in local scope but I don't see a reason to
diverge either and would prefer to have it in anonymous namespace

[Devlin, 2017/07/27 13:41:19]

Sure thing; done.

+      LAZY_SEQUENCED_TASK_RUNNER_INITIALIZER(
+          base::TaskTraits({base::MayBlock(), base::TaskPriority::BACKGROUND}));
+  return task_runner.Get();
+}
+
+void SetActivityLogTaskRunnerForTesting(base::TaskRunner* task_runner) {
+  g_task_runner_for_testing = task_runner;
+}
+
+}  // namespace extensions