Merge changes from topic "presubmit-am-93b3a992dd6c4622a633bca394ada8e5-sc-dev" into sc-mainline-prod

* changes:
  [automerge] [DO NOT MERGE] Fix Settings crash when setting a null ringtone 2p: 67b9fb57ea
  [DO NOT MERGE] Fix Settings crash when setting a null ringtone

src/com/android/settings/DefaultRingtonePreference.java

@@ -46,6 +46,11 @@ public class DefaultRingtonePreference extends RingtonePreference {
 
     @Override
     protected void onSaveRingtone(Uri ringtoneUri) {
+        if (ringtoneUri == null) {
+            setActualDefaultRingtoneUri(ringtoneUri);
+            return;
+        }
+
         String mimeType = getContext().getContentResolver().getType(ringtoneUri);
         if (mimeType == null) {
             Log.e(TAG, "onSaveRingtone for URI:" + ringtoneUri