Base implementation of WFC disclaimer UI

Test: manual - Check that no error occurred when changing the wifi
calling settings to turn on.
Test: auto - Passed WifiCallingSettingsForSubTest,
WifiCallingDisclaimerFragmentTest and DisclaimerItemListAdapterTest.
Bug: 67872298

Change-Id: I789f530d3e16baa6e56feaa4269f6696976f747e
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index fac4253..97ff613 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -159,6 +159,7 @@
     public static class WebViewAppPickerActivity extends SettingsActivity { /* empty */ }
     public static class AdvancedConnectedDeviceActivity extends SettingsActivity { /* empty */ }
     public static class BluetoothDeviceDetailActivity extends SettingsActivity { /* empty */ }
+    public static class WifiCallingDisclaimerActivity extends SettingsActivity { /* empty */ }
 
     // Top level categories for new IA
     public static class NetworkDashboardActivity extends SettingsActivity {}