Revert "Revert "Merge commit '8fcb290' into merge""

This reverts commit 57859c54de05e42b8c26a66e58e9e85bf768da46.
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index 6f828db..b996f69 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -151,7 +151,6 @@
     private static final String PREF_CARRIERS_ALPHATAG_PREFIX = "carrier_alphtag_";
     private static final String PREF_CARRIERS_NUMBER_PREFIX = "carrier_number_";
     private static final String PREF_CARRIERS_SUBSCRIBER_PREFIX = "carrier_subscriber_";
-    private static final String PREF_ENABLE_VIDEO_CALLING = "enable_video_calling";
 
     /**
      * A request object to use for transmitting data to an ICC.
@@ -2629,9 +2628,7 @@
     @Override
     public void enableVideoCalling(boolean enable) {
         enforceModifyPermission();
-        SharedPreferences.Editor editor = mTelephonySharedPreferences.edit();
-        editor.putBoolean(PREF_ENABLE_VIDEO_CALLING, enable);
-        editor.commit();
+        ImsManager.setVtSetting(mPhone.getContext(), enable);
     }
 
     @Override
@@ -2646,7 +2643,7 @@
         // which can support video calling.
         return ImsManager.isVtEnabledByPlatform(mPhone.getContext())
                 && ImsManager.isEnhanced4gLteModeSettingEnabledByUser(mPhone.getContext())
-                && mTelephonySharedPreferences.getBoolean(PREF_ENABLE_VIDEO_CALLING, true);
+                && ImsManager.isVtEnabledByUser(mPhone.getContext());
     }
 
     @Override