Add an experiment to redirect SequencedWorkerPool tasks to TaskScheduler.

base/threading/sequenced_worker_pool.h

Index: base/threading/sequenced_worker_pool.h
diff --git a/base/threading/sequenced_worker_pool.h b/base/threading/sequenced_worker_pool.h
index 4d90f920830c87fb2166b9cdd961a05c49783de0..85f902a316c400c3dd7e77a79eccc5fbcf675d98 100644
--- a/base/threading/sequenced_worker_pool.h
+++ b/base/threading/sequenced_worker_pool.h
@@ -172,6 +172,15 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   // PostSequencedWorkerTask(). Valid tokens are always nonzero.
   static SequenceToken GetSequenceToken();
 
+  // Invoke this once on the main thread of a process, before any other threads

[brettw, 2016/08/12 19:30:00]

This should have a reference to a bug to remove it.

[gab, 2016/08/12 23:27:46]

Done.

+  // are created and before any tasks are posted to that process'
+  // SequencedWorkerPools but after TaskScheduler was instantiated, to force all
+  // SequencedWorkerPools in that process to redirect their tasks to the
+  // TaskScheduler. Note: SequencedWorkerPool instances with |max_threads == 1|
+  // will be special cased to send all of their work as
+  // ExecutionMode::SINGLE_THREADED.
+  static void RedirectSequencedWorkerPoolsToTaskSchedulerForProcess();
+
   // When constructing a SequencedWorkerPool, there must be a
   // ThreadTaskRunnerHandle on the current thread unless you plan to
   // deliberately leak it.