Add an experiment to redirect DOMStorageTaskRunner to TaskScheduler.

content/browser/dom_storage/dom_storage_task_runner.cc

Index: content/browser/dom_storage/dom_storage_task_runner.cc
diff --git a/content/browser/dom_storage/dom_storage_task_runner.cc b/content/browser/dom_storage/dom_storage_task_runner.cc
index c0d00d55d6e5f29342a512d6197e8b8e893e6e06..21eb54dfc9f379c401b85ca2bd558e21f1e59f16 100644
--- a/content/browser/dom_storage/dom_storage_task_runner.cc
+++ b/content/browser/dom_storage/dom_storage_task_runner.cc
@@ -4,6 +4,8 @@
 
 #include "content/browser/dom_storage/dom_storage_task_runner.h"
 
+#include <utility>
+
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
@@ -15,20 +17,12 @@ namespace content {
 // DOMStorageWorkerPoolTaskRunner
 
 DOMStorageWorkerPoolTaskRunner::DOMStorageWorkerPoolTaskRunner(
-    base::SequencedWorkerPool* sequenced_worker_pool,
-    base::SequencedWorkerPool::SequenceToken primary_sequence_token,
-    base::SequencedWorkerPool::SequenceToken commit_sequence_token,
-    base::SingleThreadTaskRunner* delayed_task_task_runner)
-    : task_runner_(delayed_task_task_runner),
-      sequenced_worker_pool_(sequenced_worker_pool),
-      primary_sequence_token_(primary_sequence_token),
-      commit_sequence_token_(commit_sequence_token) {
-  primary_sequence_checker_.DetachFromSequence();
-  commit_sequence_checker_.DetachFromSequence();
-}
+    scoped_refptr<base::SequencedTaskRunner> primary_sequence,
+    scoped_refptr<base::SequencedTaskRunner> commit_sequence)
+    : primary_sequence_(std::move(primary_sequence)),
+      commit_sequence_(std::move(commit_sequence)) {}
 
-DOMStorageWorkerPoolTaskRunner::~DOMStorageWorkerPoolTaskRunner() {
-}
+DOMStorageWorkerPoolTaskRunner::~DOMStorageWorkerPoolTaskRunner() = default;
 
 bool DOMStorageWorkerPoolTaskRunner::RunsTasksOnCurrentThread() const {
   // It is valid for an implementation to always return true.
@@ -39,61 +33,39 @@ bool DOMStorageWorkerPoolTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
-  // Note base::TaskRunner implements PostTask in terms of PostDelayedTask
-  // with a delay of zero, we detect that usage and avoid the unecessary
-  // trip thru the message loop.
-  if (delay.is_zero()) {
-    return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
-        primary_sequence_token_, from_here, task,
-        base::SequencedWorkerPool::BLOCK_SHUTDOWN);
-  }
-  // Post a task to call this->PostTask() after the delay.
-  return task_runner_->PostDelayedTask(
-      FROM_HERE,
-      base::Bind(base::IgnoreResult(&DOMStorageWorkerPoolTaskRunner::PostTask),
-                 this, from_here, task),
-      delay);
+  return primary_sequence_->PostDelayedTask(from_here, task, delay);
 }
 
 bool DOMStorageWorkerPoolTaskRunner::PostShutdownBlockingTask(
     const tracked_objects::Location& from_here,
     SequenceID sequence_id,
     const base::Closure& task) {
-  return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
-      IDtoToken(sequence_id), from_here, task,
-      base::SequencedWorkerPool::BLOCK_SHUTDOWN);
+  return GetSequencedTaskRunner(sequence_id)->PostTask(from_here, task);
 }
 
 void DOMStorageWorkerPoolTaskRunner::AssertIsRunningOnPrimarySequence() const {
-  DCHECK(primary_sequence_checker_.CalledOnValidSequence());
+  DCHECK(primary_sequence_->RunsTasksOnCurrentThread());
 }
 
 void DOMStorageWorkerPoolTaskRunner::AssertIsRunningOnCommitSequence() const {
-  DCHECK(commit_sequence_checker_.CalledOnValidSequence());
+  DCHECK(commit_sequence_->RunsTasksOnCurrentThread());
 }
 
 scoped_refptr<base::SequencedTaskRunner>
 DOMStorageWorkerPoolTaskRunner::GetSequencedTaskRunner(SequenceID sequence_id) {
-  return sequenced_worker_pool_->GetSequencedTaskRunner(IDtoToken(sequence_id));
-}
-
-base::SequencedWorkerPool::SequenceToken
-DOMStorageWorkerPoolTaskRunner::IDtoToken(SequenceID id) const {
-  if (id == PRIMARY_SEQUENCE)
-    return primary_sequence_token_;
-  DCHECK_EQ(COMMIT_SEQUENCE, id);
-  return commit_sequence_token_;
+  if (sequence_id == PRIMARY_SEQUENCE)
+    return primary_sequence_;
+  DCHECK_EQ(COMMIT_SEQUENCE, sequence_id);
+  return commit_sequence_;
 }
 
 // MockDOMStorageTaskRunner
 
 MockDOMStorageTaskRunner::MockDOMStorageTaskRunner(
-    base::SingleThreadTaskRunner* task_runner)
-    : task_runner_(task_runner) {
-}
+    scoped_refptr<base::SequencedTaskRunner> task_runner)
+    : task_runner_(std::move(task_runner)) {}
 
-MockDOMStorageTaskRunner::~MockDOMStorageTaskRunner() {
-}
+MockDOMStorageTaskRunner::~MockDOMStorageTaskRunner() = default;
 
 bool MockDOMStorageTaskRunner::RunsTasksOnCurrentThread() const {
   return task_runner_->RunsTasksOnCurrentThread();