Add contentDescription for compact action_mode_close_item

Fix bug 6219630

Change-Id: I551624466d02f5d31be7030518b0d47b3b7f03b5

Author: adamp

core/res/res/layout/action_mode_close_item.xml

@@ -19,6 +19,7 @@
         android:focusable="true"
         android:clickable="true"
         android:paddingLeft="8dip"
+        android:contentDescription="@string/action_mode_done"
         style="?android:attr/actionModeCloseButtonStyle"
         android:layout_width="wrap_content"
         android:layout_height="match_parent"