Cleanup: Remove more unneeded browser_thread.h includes.

chrome/browser/history/download_database.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 "chrome/browser/history/download_database.h"
 
 #include <limits>
 #include <string>
 #include <vector>
 
 #include "base/debug/alias.h"
 #include "base/file_path.h"
 #include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/history/download_row.h"
-#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_item.h"
 #include "sql/statement.h"
 
 using content::DownloadItem;
 
 namespace history {
 
 // static
 const int64 DownloadDatabase::kUninitializedHandle = -1;
 
@@ skipping 235 matching lines @@
 }
 
 int DownloadDatabase::CountDownloads() {
   sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "SELECT count(*) from downloads"));
   statement.Step();
   return statement.ColumnInt(0);
 }
 
 }  // namespace history