Update some uses of UTF conversions in chrome/browser to use the base:: namespace.

chrome/browser/signin/signin_names_io_thread.cc

Index: chrome/browser/signin/signin_names_io_thread.cc
diff --git a/chrome/browser/signin/signin_names_io_thread.cc b/chrome/browser/signin/signin_names_io_thread.cc
index e1f7b317cae2f1afebaef06be7a60b9ac5ed2f01..0a795090e4c4a96d540f81a659da612e246fdaea 100644
--- a/chrome/browser/signin/signin_names_io_thread.cc
+++ b/chrome/browser/signin/signin_names_io_thread.cc
@@ -65,13 +65,13 @@ void SigninNamesOnIOThread::Observe(
     case chrome::NOTIFICATION_GOOGLE_SIGNIN_SUCCESSFUL: {
       const GoogleServiceSigninSuccessDetails* signin_details =
           content::Details<GoogleServiceSigninSuccessDetails>(details).ptr();
-      PostTaskToIOThread(type, UTF8ToUTF16(signin_details->username));
+      PostTaskToIOThread(type, base::UTF8ToUTF16(signin_details->username));
       break;
     }
     case chrome::NOTIFICATION_GOOGLE_SIGNED_OUT: {
       const GoogleServiceSignoutDetails* signout_details =
           content::Details<GoogleServiceSignoutDetails>(details).ptr();
-      PostTaskToIOThread(type, UTF8ToUTF16(signout_details->username));
+      PostTaskToIOThread(type, base::UTF8ToUTF16(signout_details->username));
       break;
     }
     default: