gtk: Show a tooltip for the location icon in the omnibox.

chrome/browser/ui/gtk/location_bar_view_gtk.cc

Index: chrome/browser/ui/gtk/location_bar_view_gtk.cc
diff --git a/chrome/browser/ui/gtk/location_bar_view_gtk.cc b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
index 4fc55aa4cc1f4c10e9a5e54f0c679caca991151d..1b8859d67c2c7b14d0f9ed1d404fecdb29a690de 100644
--- a/chrome/browser/ui/gtk/location_bar_view_gtk.cc
+++ b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
@@ -353,6 +353,9 @@ void LocationBarViewGtk::BuildSiteTypeArea() {
   gtk_box_pack_start(GTK_BOX(hbox_.get()), site_type_alignment_,
                      FALSE, FALSE, 0);
 
+  gtk_widget_set_tooltip_text(location_icon_image_,
+      l10n_util::GetStringUTF8(IDS_TOOLTIP_LOCATION_ICON).c_str());
+
   g_signal_connect(site_type_event_box_, "button-release-event",
                    G_CALLBACK(&OnIconReleasedThunk), this);
 }