Make GetBestPageForOnlineURL async

components/offline_pages/offline_page_model_impl.cc

 // Copyright 2016 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/offline_pages/offline_page_model_impl.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/bind.h"
@@ skipping 548 matching lines @@
   // Getting pages by offline URL does not exclude expired pages, as the caller
   // already holds the offline URL and simply needs to look up a corresponding
   // online URL.
   for (const auto& id_page_pair : offline_pages_) {
     if (id_page_pair.second.GetOfflineURL() == offline_url)
       return &(id_page_pair.second);
   }
   return nullptr;
 }
 
-void OfflinePageModelImpl::GetBestPageForOnlineURL(
-    const GURL& online_url,
-    const SingleOfflinePageItemCallback callback) {
-  RunWhenLoaded(
-      base::Bind(&OfflinePageModelImpl::GetBestPageForOnlineURLWhenLoadDone,
-                 weak_ptr_factory_.GetWeakPtr(), online_url, callback));
-}
-
-void OfflinePageModelImpl::GetBestPageForOnlineURLWhenLoadDone(
-    const GURL& online_url,
-    const SingleOfflinePageItemCallback& callback) const {
-  callback.Run(MaybeGetBestPageForOnlineURL(online_url));
-}
-
 void OfflinePageModelImpl::GetPagesByOnlineURL(
     const GURL& online_url,
     const MultipleOfflinePageItemCallback& callback) {
   RunWhenLoaded(
       base::Bind(&OfflinePageModelImpl::GetPagesByOnlineURLWhenLoadDone,
                  weak_ptr_factory_.GetWeakPtr(), online_url, callback));
 }
 
 void OfflinePageModelImpl::GetPagesByOnlineURLWhenLoadDone(
     const GURL& online_url,
@@ skipping 478 matching lines @@
 void OfflinePageModelImpl::RunWhenLoaded(const base::Closure& task) {
   if (!is_loaded_) {
     delayed_tasks_.push_back(task);
     return;
   }
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, task);
 }
 
 }  // namespace offline_pages