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

chrome/browser/autocomplete/zero_suggest_provider.cc

Index: chrome/browser/autocomplete/zero_suggest_provider.cc
diff --git a/chrome/browser/autocomplete/zero_suggest_provider.cc b/chrome/browser/autocomplete/zero_suggest_provider.cc
index f2fb93b7a2d15714084c6d0562279d37c00ca215..f29b0f133a0bc314d5a603be25036e26bb865273 100644
--- a/chrome/browser/autocomplete/zero_suggest_provider.cc
+++ b/chrome/browser/autocomplete/zero_suggest_provider.cc
@@ -258,7 +258,8 @@ void ZeroSuggestProvider::FillResults(
       relevances = NULL;
     if (types && types->GetString(index, &type) && (type == "NAVIGATION")) {
       // Do not blindly trust the URL coming from the server to be valid.
-      GURL url(URLFixerUpper::FixupURL(UTF16ToUTF8(result), std::string()));
+      GURL url(URLFixerUpper::FixupURL(
+          base::UTF16ToUTF8(result), std::string()));
       if (url.is_valid()) {
         if (descriptions != NULL)
           descriptions->GetString(index, &title);