shill: Update to build against libchrome-271506.

BUG=chromium:375032
TEST=`USE='cellular gdmwimax wimax vpn' FEATURES=test emerge-$BOARD platform2`

Change-Id: Ib7c8b2b290caa261cbb61d30cf8a361a1e3345e1
Reviewed-on: https://chromium-review.googlesource.com/201211
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
diff --git a/file_reader.cc b/file_reader.cc
index d0021a4..fb916d3 100644
--- a/file_reader.cc
+++ b/file_reader.cc
@@ -4,6 +4,8 @@
 
 #include "shill/file_reader.h"
 
+#include <base/file_util.h>
+
 using base::FilePath;
 using std::string;