Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/null_idle_task_runner.cc

 // Copyright 2014 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 "content/browser/appcache/mock_appcache_policy.h"
+#include "content/child/scheduler/null_idle_task_runner.h"
 
 namespace content {
 
-MockAppCachePolicy::MockAppCachePolicy()
-    : can_load_return_value_(true), can_create_return_value_(true) {
+NullIdleTaskRunner::NullIdleTaskRunner()
+    : SingleThreadIdleTaskRunner(nullptr,
+                                 nullptr,
+                                 base::Callback<void(base::TimeTicks*)>(),
+                                 "null.taskrunner") {
 }
 
-MockAppCachePolicy::~MockAppCachePolicy() {
+NullIdleTaskRunner::~NullIdleTaskRunner() {
 }
 
-bool MockAppCachePolicy::CanLoadAppCache(const GURL& manifest_url,
-                                         const GURL& first_party) {
-  requested_manifest_url_ = manifest_url;
-  return can_load_return_value_;
+void NullIdleTaskRunner::PostIdleTask(
+    const tracked_objects::Location& from_here,
+    const IdleTask& idle_task) {
 }
 
-bool MockAppCachePolicy::CanCreateAppCache(const GURL& manifest_url,
-                                           const GURL& first_party) {
-  requested_manifest_url_ = manifest_url;
-  return can_create_return_value_;
+void NullIdleTaskRunner::PostNonNestableIdleTask(
+    const tracked_objects::Location& from_here,
+    const IdleTask& idle_task) {
+}
+
+void NullIdleTaskRunner::PostIdleTaskAfterWakeup(
+  const tracked_objects::Location& from_here,
+  const IdleTask& idle_task) {
 }
 
 }  // namespace content