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

chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc

Index: chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc
diff --git a/chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc b/chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc
index 65d0b421644d244be1302beedfd1b23386e570b5..6c833f51eb93012503a327a0cd7a7f63ef2959d5 100644
--- a/chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc
+++ b/chrome/browser/ui/gtk/avatar_menu_bubble_gtk.cc
@@ -184,7 +184,7 @@ void AvatarMenuBubbleGtk::InitManagedUserContents() {
       theme_service_->BuildLabel(std::string(), ui::kGdkBlack);
   char* markup = g_markup_printf_escaped(
       "<span size='small'>%s</span>",
-      UTF16ToUTF8(avatar_menu_->GetManagedUserInformation()).c_str());
+      base::UTF16ToUTF8(avatar_menu_->GetManagedUserInformation()).c_str());
   const int kLabelWidth = 150;
   gtk_widget_set_size_request(status_label, kLabelWidth, -1);
   gtk_label_set_markup(GTK_LABEL(status_label), markup);