chrome 3: string_util.h -> utf_string_conversions.h fix.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/671014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@40959 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/metrics/metrics_log.cc b/chrome/browser/metrics/metrics_log.cc
index dd4aa3f..37a6b7f 100644
--- a/chrome/browser/metrics/metrics_log.cc
+++ b/chrome/browser/metrics/metrics_log.cc
@@ -12,6 +12,7 @@
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
 #include "base/sys_info.h"
+#include "base/utf_string_conversions.h"
 #include "base/third_party/nspr/prtime.h"
 #include "chrome/browser/autocomplete/autocomplete.h"
 #include "chrome/browser/browser_process.h"