AU: Class to perform delta updates.

A class to perform delta updates and the associated unittests. Also,
change the delta diff generator executable to be able to apply a
delta, which is handy for debugging.

TEST=Attached unit test, hand-tested on real build images
BUG=552

Review URL: http://codereview.chromium.org/1718001
diff --git a/update_check_action.h b/update_check_action.h
index 5622a63..da48aba 100644
--- a/update_check_action.h
+++ b/update_check_action.h
@@ -5,8 +5,8 @@
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_CHECK_ACTION_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_CHECK_ACTION_H__
 
-#include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <fcntl.h>
 
 #include <string>
@@ -14,8 +14,8 @@
 #include <curl/curl.h>
 
 #include "base/scoped_ptr.h"
-#include "action.h"
-#include "http_fetcher.h"
+#include "update_engine/action.h"
+#include "update_engine/http_fetcher.h"
 
 // The Update Check action makes an update check request to Omaha and
 // can output the response on the output ActionPipe.