Bug 1629474 - Avoid warnings when initializing empty editors. r=masayuki

Differential Revision: https://phabricator.services.mozilla.com/D70669

--HG--
extra : moz-landing-system : lando

editor/libeditor/TextEditor.cpp

@@ -139,11 +139,18 @@ nsresult TextEditor::Init(Document& aDoc, Element* aRoot,
     return NS_ERROR_FAILURE;
   }
 
+  // We set mInitSucceeded here rather than at the end of the function,
+  // since InitEditorContentAndSelection() can perform some transactions
+  // and can warn if mInitSucceeded is still false.
+  MOZ_ASSERT(!mInitSucceeded, "TextEditor::Init() shouldn't be nested");
+  mInitSucceeded = true;
+
   rv = InitEditorContentAndSelection();
   if (NS_FAILED(rv)) {
     NS_WARNING("TextEditor::InitEditorContentAndSelection() failed");
     // XXX Sholdn't we expose `NS_ERROR_EDITOR_DESTROYED` even though this
     //     is a public method?
+    mInitSucceeded = false;
     return EditorBase::ToGenericNSResult(rv);
   }
 
@@ -151,8 +158,6 @@ nsresult TextEditor::Init(Document& aDoc, Element* aRoot,
   // we're initializing the editor.
   ClearUndoRedo();
   EnableUndoRedo();
-  MOZ_ASSERT(!mInitSucceeded, "TextEditor::Init() shouldn't be nested");
-  mInitSucceeded = true;
   return NS_OK;
 }