AU: Try delta updates first, then full updates

src/platform/update_engine/download_action.h

 // Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_DOWNLOAD_ACTION_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_DOWNLOAD_ACTION_H__
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 
-#include <map>
 #include <string>
 
 #include <curl/curl.h>
 
 #include "base/scoped_ptr.h"
 #include "update_engine/action.h"
 #include "update_engine/decompressing_file_writer.h"
 #include "update_engine/file_writer.h"
 #include "update_engine/http_fetcher.h"
 #include "update_engine/install_plan.h"
 #include "update_engine/omaha_hash_calculator.h"
 
 // The Download Action downloads a requested url to a specified path on disk.
 // The url and output path are determined by the InstallPlan passed in.
 
-using std::map;
-using std::string;
-
 namespace chromeos_update_engine {
 
 class DownloadAction;
 class NoneType;
 
 template<>
 class ActionTraits<DownloadAction> {
  public:
   // Takes and returns an InstallPlan
   typedef InstallPlan InputObjectType;
@@ skipping 57 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(DownloadAction);
 };
 
 // We want to be sure that we're compiled with large file support on linux,
 // just in case we find ourselves downloading large images.
 COMPILE_ASSERT(8 == sizeof(off_t), off_t_not_64_bit);
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DOWNLOAD_ACTION_H__