views: Refactor the way we get the combo box font.

ui/views/controls/combobox/combobox.h

Index: ui/views/controls/combobox/combobox.h
diff --git a/ui/views/controls/combobox/combobox.h b/ui/views/controls/combobox/combobox.h
index a6f7e351613bd692a52343d49eace92951fe902d..77fc9844ba6c14cc457e2a5219c16a212ca9cba4 100644
--- a/ui/views/controls/combobox/combobox.h
+++ b/ui/views/controls/combobox/combobox.h
@@ -12,6 +12,10 @@
 #include "ui/views/controls/combobox/native_combobox_wrapper.h"
 #include "ui/views/view.h"
 
+namespace gfx {
+class Font;
+}
+
 namespace ui {
 class ComboboxModel;
 }
@@ -30,6 +34,8 @@ class VIEWS_EXPORT Combobox : public View {
   explicit Combobox(ui::ComboboxModel* model);
   virtual ~Combobox();
 
+  static const gfx::Font& GetFont();
+
   // Register |listener| for item change events.
   void set_listener(ComboboxListener* listener) {
     listener_ = listener;