Fix for 29843 -- caret disappears on delete. r=jfrancis

editor/base/nsHTMLEditor.cpp

@@ -5662,6 +5662,8 @@ nsHTMLEditor::CollapseAdjacentTextNodes(nsIDOMRange *aInRange)
   iter->Init(aInRange);
   nsCOMPtr<nsIContent> content;
   result = iter->CurrentNode(getter_AddRefs(content));  
+  if (!content) return NS_OK;
+  
   while (NS_ENUMERATOR_FALSE == iter->IsDone())
   {
     nsCOMPtr<nsIDOMCharacterData> text = do_QueryInterface(content);

editor/libeditor/html/nsHTMLEditor.cpp

@@ -5662,6 +5662,8 @@ nsHTMLEditor::CollapseAdjacentTextNodes(nsIDOMRange *aInRange)
   iter->Init(aInRange);
   nsCOMPtr<nsIContent> content;
   result = iter->CurrentNode(getter_AddRefs(content));  
+  if (!content) return NS_OK;
+  
   while (NS_ENUMERATOR_FALSE == iter->IsDone())
   {
     nsCOMPtr<nsIDOMCharacterData> text = do_QueryInterface(content);