[Extensions][TaskScheduler] Update ActivityLog for scheduling migration

chrome/browser/extensions/activity_log/activity_log_task_runner.h

Index: chrome/browser/extensions/activity_log/activity_log_task_runner.h
diff --git a/chrome/browser/extensions/activity_log/activity_log_task_runner.h b/chrome/browser/extensions/activity_log/activity_log_task_runner.h
new file mode 100644
index 0000000000000000000000000000000000000000..35e701a2ac21a875378143a17256d7657294842d
--- /dev/null
+++ b/chrome/browser/extensions/activity_log/activity_log_task_runner.h
@@ -0,0 +1,22 @@
+// 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.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_TASK_RUNNER_H_
+#define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_TASK_RUNNER_H_
+
+#include "base/memory/ref_counted.h"
+
+namespace base {
+class TaskRunner;
+}
+
+namespace extensions {
+
+const scoped_refptr<base::TaskRunner> GetActivityLogTaskRunner();
+
+void SetActivityLogTaskRunnerForTesting(base::TaskRunner* task_runner);

[Devlin, 2017/07/10 18:48:39]

This appears to be needed for activity log unittests.  Without setting the
runner here, the sql database always fails to open with a disk I/O error; other
similar areas of the code using sql databases seem to do the same thing in unit
testing.  I've tried adding a ScopedTaskEnvironment, but no luck.

gab@, is this expected/correct?  Or should there be a way of running a sql
database in a unittest with a constructed task runner?

[gab, 2017/07/12 00:30:22]

This is a ChromeRenderViewHostTestHarness which has a TestBrowserThreadBundle
(which provides a ScopedTaskEnvironment equivalent so you already have a
TaskScheduler)
This is because the unit tests previously depended on TestBrowserThreadBundle
faking the DB thread on the main thread (such that "async" work would execute as
part of RunLoop::Run()), now you need to
content::RunAllBlockingPoolTasksUntilIdle() instead to flush main thread *and*
async work.

Or doing what you did ForTesting is also fine (though IMO not as clean) if you
prefer to keep everything on the main thread for the unit test.

+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_TASK_RUNNER_H_