Derive DomStorageTaskRunner from base::TaskRunner now that it exists.

webkit/dom_storage/dom_storage_task_runner.cc

 // Copyright (c) 2012 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 "webkit/dom_storage/dom_storage_task_runner.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/message_loop_proxy.h"
 #include "base/tracked_objects.h"
 
 namespace dom_storage {
 
 // DomStorageTaskRunner
 
 DomStorageTaskRunner::DomStorageTaskRunner(
     base::MessageLoopProxy* message_loop)
     : message_loop_(message_loop) {
 }
 
 DomStorageTaskRunner::~DomStorageTaskRunner() {
 }
 
-bool DomStorageTaskRunner::PostTask(
-    const tracked_objects::Location& from_here,
-    const base::Closure& task) {
-  return message_loop_->PostTask(from_here, task);
-}
-
 bool DomStorageTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
   return message_loop_->PostDelayedTask(from_here, task, delay);
 }
 
+bool DomStorageTaskRunner::PostDelayedTask(
+    const tracked_objects::Location& from_here,
+    const base::Closure& task,
+    int64 delay_ms) {
+  return PostDelayedTask(
+      from_here, task, base::TimeDelta::FromMilliseconds(delay_ms));
+}
+
+bool DomStorageTaskRunner::RunsTasksOnCurrentThread() const {
+  return true;
+}
+
 // DomStorageWorkerPoolTaskRunner
 
 DomStorageWorkerPoolTaskRunner::DomStorageWorkerPoolTaskRunner(
     base::SequencedWorkerPool* sequenced_worker_pool,
+    base::SequencedWorkerPool::SequenceToken sequence_token,
     base::MessageLoopProxy* delayed_task_loop)
     : DomStorageTaskRunner(delayed_task_loop),
       sequenced_worker_pool_(sequenced_worker_pool),
-      sequence_token_(
-          sequenced_worker_pool->GetNamedSequenceToken("dom_storage_token")) {
+      sequence_token_(sequence_token) {
 }
 
 DomStorageWorkerPoolTaskRunner::~DomStorageWorkerPoolTaskRunner() {
 }
 
-bool DomStorageWorkerPoolTaskRunner::PostTask(
-    const tracked_objects::Location& from_here,
-    const base::Closure& task) {
-  // We can skip on shutdown as the destructor of DomStorageArea will ensure
-  // that any remaining data is committed to disk.
-  return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
-      sequence_token_, from_here, task,
-      base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
-}
-
 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 == base::TimeDelta()) {
+    // We can skip on shutdown as the destructor of DomStorageArea will ensure
+    // that any remaining data is committed to disk.
+    return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
+        sequence_token_, from_here, task,
+        base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  }
   // Post a task to call this->PostTask() after the delay.
   return message_loop_->PostDelayedTask(
       FROM_HERE,
       base::Bind(base::IgnoreResult(&DomStorageWorkerPoolTaskRunner::PostTask),
                  this, from_here, task),
       delay);
 }
 
 // MockDomStorageTaskRunner
 
 MockDomStorageTaskRunner::MockDomStorageTaskRunner(
     base::MessageLoopProxy* message_loop)
     : DomStorageTaskRunner(message_loop) {
 }
 
 bool MockDomStorageTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
-  // Don't wait in unit tests.
-  return PostTask(from_here, task);
+  // Squash all delays to zero in our mock.
+  return DomStorageTaskRunner::PostDelayedTask(
+      from_here, task, base::TimeDelta());
 }
 
 }  // namespace dom_storage