Add Open Source licenses in about menu.

- Add command line switch for privacy policy url and eula url.

- Consolidate all browser switches inside BrowserSwitches class.

Change-Id: If0257c0e34e030a2619cb5957ad8c852c5a49633
diff --git a/res/xml/about_preferences.xml b/res/xml/about_preferences.xml
index 14bab64..2b156fa 100644
--- a/res/xml/about_preferences.xml
+++ b/res/xml/about_preferences.xml
@@ -56,4 +56,10 @@
     <Preference
         android:key="feedback"
         android:title="@string/feedback" />
+
+    <Preference
+        android:key="legal"
+        android:title="@string/swe_legal"
+        android:summary="@string/swe_pref_legal_info_summary"/>
+
 </PreferenceScreen>