Bug 1402196 - Part 1. Don't add null range to aArrayOfRanges. r=masayuki

RangeItem::GetRange can return null, so we shouldn't add null range to
aArrayOfRanges.

MozReview-Commit-ID: Ci5VHeqE8km

--HG--
extra : rebase_source : 83abb5f4ea405c360e63b7ed73530a7321a2a1e5

editor/libeditor/HTMLEditRules.cpp

@@ -5893,7 +5893,10 @@ HTMLEditRules::GetNodesForOperation(
     // Then unregister the ranges
     for (auto& item : rangeItemArray) {
       htmlEditor->mRangeUpdater.DropRangeItem(item);
-      aArrayOfRanges.AppendElement(item->GetRange());
+      RefPtr<nsRange> range = item->GetRange();
+      if (range) {
+        aArrayOfRanges.AppendElement(range);
+      }
     }
     NS_ENSURE_SUCCESS(rv, rv);
   }