Componentize component_updater: Replace content::BrowserThread usage with task runners

chrome/browser/component_updater/update_checker.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 "chrome/browser/component_updater/update_checker.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
+#include "base/threading/thread_checker.h"
 #include "chrome/browser/component_updater/component_updater_configurator.h"
 #include "chrome/browser/component_updater/component_updater_utils.h"
 #include "chrome/browser/component_updater/crx_update_item.h"
-#include "content/public/browser/browser_thread.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
-using content::BrowserThread;
-
 namespace component_updater {
 
 // Builds an update check request for |components|. |additional_attributes| is
 // serialized as part of the <request> element of the request to customize it
 // with data that is not platform or component specific. For each |item|, a
 // corresponding <app> element is created and inserted as a child node of
 // the <request>.
 //
 // An app element looks like this:
 //    <app appid="hnimpnehoodheedghdeeijklkeaacbdc"
@@ skipping 51 matching lines @@
 
   // Overrides for UrlFetcher.
   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
 
  private:
   const Configurator& config_;
   const UpdateCheckCallback update_check_callback_;
 
   scoped_ptr<net::URLFetcher> url_fetcher_;
 
+  base::ThreadChecker thread_checker_;
+
   DISALLOW_COPY_AND_ASSIGN(UpdateCheckerImpl);
 };
 
 scoped_ptr<UpdateChecker> UpdateChecker::Create(
     const Configurator& config,
     const UpdateCheckCallback& update_check_callback) {
   scoped_ptr<UpdateCheckerImpl> update_checker(
       new UpdateCheckerImpl(config, update_check_callback));
   return update_checker.PassAs<UpdateChecker>();
 }
 
 UpdateCheckerImpl::UpdateCheckerImpl(
     const Configurator& config,
     const UpdateCheckCallback& update_check_callback)
     : config_(config), update_check_callback_(update_check_callback) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
 UpdateCheckerImpl::~UpdateCheckerImpl() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 bool UpdateCheckerImpl::CheckForUpdates(
     const std::vector<CrxUpdateItem*>& items_to_check,
     const std::string& additional_attributes) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(thread_checker_.CalledOnValidThread());
 
   if (url_fetcher_)
     return false;  // Another fetch is in progress.
 
   url_fetcher_.reset(SendProtocolRequest(
       config_.UpdateUrl(),
       BuildUpdateCheckRequest(config_, items_to_check, additional_attributes),
       this,
       config_.RequestContext()));
 
   return true;
 }
 
 void UpdateCheckerImpl::OnURLFetchComplete(const net::URLFetcher* source) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(url_fetcher_.get() == source);
 
   int error = 0;
   std::string error_message;
   UpdateResponse update_response;
 
   if (FetchSuccess(*source)) {
     std::string xml;
     source->GetResponseAsString(&xml);
     if (!update_response.Parse(xml)) {
       error = -1;
       error_message = update_response.errors();
       VLOG(1) << "Update request failed: " << error_message;
     }
   } else {
     error = GetFetchError(*source);
     error_message.assign("network error");
     VLOG(1) << "Update request failed: network error";
   }
 
   url_fetcher_.reset();
   update_check_callback_.Run(error, error_message, update_response.results());
 }
 
 }  // namespace component_updater