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

chrome/browser/ui/libgtk2ui/gtk2_ui.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_
 #define CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 37 matching lines @@
   typedef std::map<int, color_utils::HSL> TintMap;
   typedef std::map<int, gfx::Image*> ImageCache;
 
   // This method returns the colors webkit will use for the scrollbars. When no
   // colors are specified by the GTK+ theme, this function averages of the
   // thumb part and of the track colors.
   void GetScrollbarColors(GdkColor* thumb_active_color,
                           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();
 
   // Reads in explicit theme frame colors from the ChromeGtkFrame style class
   // or generates them per our fallback algorithm.
   GdkColor BuildFrameColors(GtkStyle* frame_style);
 
   // Sets the underlying theme colors/tints from a GTK color.
   void SetThemeColorFromGtk(int id, const GdkColor* color);
@@ skipping 84 matching lines @@
 }  // namespace libgtk2ui
 
 // Access point to the GTK2 desktop system. This should be the only symbol that
 // is exported in the library; everything else should be used through the
 // interface, because eventually this .so will be loaded through dlopen at
 // runtime so our main binary can conditionally load GTK2 or GTK3 or EFL or
 // QT or whatever.
 LIBGTK2UI_EXPORT ui::LinuxUI* BuildGtk2UI();
 
 #endif  // CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_