views: Rename ComboboxListener::ItemChanged to something more accurate.

ui/views/examples/native_theme_button_example.cc

Index: ui/views/examples/native_theme_button_example.cc
diff --git a/ui/views/examples/native_theme_button_example.cc b/ui/views/examples/native_theme_button_example.cc
index d796ba8eef6463fdcbd79343f92eb7b723440fe6..c92f1d6f35c59215618ed6932c6085674f993148 100644
--- a/ui/views/examples/native_theme_button_example.cc
+++ b/ui/views/examples/native_theme_button_example.cc
@@ -91,9 +91,7 @@ std::string ExampleNativeThemeButton::MessWithState() {
   return base::StringPrintf(message, ++count_);
 }
 
-void ExampleNativeThemeButton::ItemChanged(Combobox* combo_box,
-                                           int prev_index,
-                                           int new_index) {
+void ExampleNativeThemeButton::OnSelectedIndexChanged(Combobox* combobox) {
   SchedulePaint();
 }