Add the button style for combobox

ui/views/controls/combobox/combobox_listener.h

Index: ui/views/controls/combobox/combobox_listener.h
diff --git a/ui/views/controls/combobox/combobox_listener.h b/ui/views/controls/combobox/combobox_listener.h
index 987f4f442dc7f2772d79b200899c3a2fc09a76d6..306208f2ad59bdba77a693d3fa6c7e0740030f82 100644
--- a/ui/views/controls/combobox/combobox_listener.h
+++ b/ui/views/controls/combobox/combobox_listener.h
@@ -15,6 +15,10 @@ class ComboboxListener {
  public:
   virtual void OnSelectedIndexChanged(Combobox* combobox) = 0;
 
+  // Handles when the combobox's style is the button style and the button is
+  // clicked.
+  virtual void OnTextButtonClicked(Combobox* combobox) {}

[sky, 2013/12/02 21:28:55]

OnComboboxTextButtonClicked

[hajimehoshi, 2013/12/03 10:30:52]

Done.

+
  protected:
   virtual ~ComboboxListener() {}
 };