Add default Dialer preference to Settings

Add a Default phone app setting under wireless settings, and also
a dialog activity that allows a user to confirm the selection of an
application as a default phone app.

Bug: 6948882
Bug: 15021725
Change-Id: I2c1473feba20da01b14fbd30dbecc01be560479d

res/xml/wireless_settings.xml

@@ -4,9 +4,9 @@
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
-  
+
           http://www.apache.org/licenses/LICENSE-2.0
-  
+
      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -29,6 +29,12 @@
         android:summary="%s"
         android:persistent="false" />
 
+    <com.android.settings.AppListPreference
+        android:key="phone_application"
+        android:title="@string/phone_application_title"
+        android:summary="%s"
+        android:persistent="false" />
+
     <CheckBoxPreference
         android:key="toggle_nfc"
         android:title="@string/nfc_quick_toggle_title"