linux: Both gtk and the aura port should set the icon theme name.

chrome/browser/ui/libgtk2ui/gtk2_ui.h

Index: chrome/browser/ui/libgtk2ui/gtk2_ui.h
diff --git a/chrome/browser/ui/libgtk2ui/gtk2_ui.h b/chrome/browser/ui/libgtk2ui/gtk2_ui.h
index 55261c2c09f9dd487e46f9e18d4ae9079ec31b5d..f46c0903113674bb70a8b95bc2fa445e7ee0d12d 100644
--- a/chrome/browser/ui/libgtk2ui/gtk2_ui.h
+++ b/chrome/browser/ui/libgtk2ui/gtk2_ui.h
@@ -55,6 +55,10 @@ class Gtk2UI : public ui::LinuxUIShellDialog {
                           GdkColor* thumb_inactive_color,
                           GdkColor* track_color);
 
+  // Gets the name of the current icon theme and passes it to our low level XDG
+  // integration.
+  void SetXDGIconTheme();
+
   // Extracts colors and tints from the GTK theme, both for the
   // ThemeService interface and the colors we send to webkit.
   void LoadGtkValues();