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/AndroidManifest.xml b/AndroidManifest.xml
index cc36a30..2a8175a 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -187,6 +187,11 @@
             </intent-filter>
         </activity>
 
+        <activity android:name=".preferences.LegalPreviewActivity"
+            android:parentActivityName=".BrowserActivity"
+            android:theme="@style/SettingsTheme">
+        </activity>
+
         <activity android:name="BookmarkSearch"
                   android:label="@string/bookmarks_search"
                   android:stateNotNeeded="true"