Implement the "add word" screen according to new spec

This is only the interface. It doesn't do anything yet, so as to
avoid a too large change.

Bug: 6026080
Change-Id: I0c7f0c09f71e01b18fcb3566a3c6c4b0f0b2a0fc

src/com/android/settings/inputmethod/UserDictionaryAddWordActivity.java

@@ -41,6 +41,7 @@ import android.widget.Spinner;
 
 public class UserDictionaryAddWordActivity extends Activity
         implements AdapterView.OnItemSelectedListener {
+    public static final String EXTRA_MODE = "mode";
     public static final String EXTRA_WORD = "word";
     public static final String EXTRA_LOCALE = "locale";
     private static final int FREQUENCY_FOR_USER_DICTIONARY_ADDS = 250;