[CleanUp] Use base::STLSetDifference in place of std::set_difference

chrome/browser/download/download_history_unittest.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 <set>
 #include <vector>
 
 #include "base/rand_util.h"
 #include "base/stl_util.h"
 #include "chrome/browser/download/download_history.h"
@@ skipping 145 matching lines @@
 
   void ExpectNoDownloadsRemoved() {
     DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
     content::RunAllPendingInMessageLoop(content::BrowserThread::UI);
     EXPECT_EQ(0, static_cast<int>(remove_downloads_.size()));
   }
 
   void ExpectDownloadsRemoved(const IdSet& ids) {
     DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
     content::RunAllPendingInMessageLoop(content::BrowserThread::UI);
-    IdSet differences;
-    std::insert_iterator<IdSet> differences_iter(
-        differences, differences.begin());
-    std::set_difference(ids.begin(), ids.end(),
-                        remove_downloads_.begin(),
-                        remove_downloads_.end(),
-                        differences_iter);
+    IdSet differences = base::STLSetDifference<IdSet>(ids, remove_downloads_);
     for (IdSet::const_iterator different = differences.begin();
          different != differences.end(); ++different) {
       EXPECT_TRUE(false) << *different;
     }
     remove_downloads_.clear();
   }
 
  private:
   bool slow_create_download_;
   bool fail_create_download_;
@@ skipping 587 matching lines @@
   item_observer()->OnDownloadUpdated(&item(0));
 
   FinishCreateDownload();
   EXPECT_TRUE(DownloadHistory::IsPersisted(&item(0)));
 
   // ItemAdded should call OnDownloadUpdated, which should detect that the item
   // changed while it was being added and call UpdateDownload immediately.
   info.opened = true;
   ExpectDownloadUpdated(info);
 }