Automated IWYU fix for TaskRunner includes.

components/signin/core/browser/signin_cookie_changed_subscription.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 "components/signin/core/browser/signin_cookie_changed_subscription.h"
 
+#include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "net/cookies/cookie_store.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
 
 SigninCookieChangedSubscription::SubscriptionHolder::SubscriptionHolder() {
 }
 
 SigninCookieChangedSubscription::SubscriptionHolder::~SubscriptionHolder() {
 }
@@ skipping 77 matching lines @@
 }
 
 void SigninCookieChangedSubscription::OnCookieChanged(
     const net::CanonicalCookie& cookie,
     net::CookieStore::ChangeCause cause) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!callback_.is_null()) {
     callback_.Run(cookie, cause);
   }
 }