Re-factor Editor::unappliedEditing()

third_party/WebKit/Source/core/editing/Editor.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 857 matching lines @@
       cmd->startingRootEditableElement(), cmd->endingRootEditableElement(),
       InputEvent::InputType::HistoryUndo, nullAtom,
       InputEvent::EventIsComposing::NotComposing);
 
   // TODO(editing-dev): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   // In the long term, we should stop editing commands from storing
   // VisibleSelections as starting and ending selections.
   frame().document()->updateStyleAndLayoutIgnorePendingStylesheets();
 
-  VisibleSelection newSelection =
+  const VisibleSelection& newSelection =
       correctedVisibleSelection(cmd->startingSelection());
-  if (newSelection.start().document() == frame().document() &&
-      newSelection.end().document() == frame().document())
+  DCHECK(newSelection.isValidFor(*frame().document())) << newSelection;
+  if (!newSelection.isNone()) {
     changeSelectionAfterCommand(
         newSelection,
         FrameSelection::CloseTyping | FrameSelection::ClearTypingStyle);
+  }
 
   m_lastEditCommand = nullptr;
   m_undoStack->registerRedoStep(cmd);
   respondToChangedContents(newSelection);
 }
 
 void Editor::reappliedEditing(EditCommandComposition* cmd) {
   EventQueueScope scope;
 
   dispatchEditableContentChangedEvents(cmd->startingRootEditableElement(),
@@ skipping 761 matching lines @@
 }
 
 DEFINE_TRACE(Editor) {
   visitor->trace(m_frame);
   visitor->trace(m_lastEditCommand);
   visitor->trace(m_undoStack);
   visitor->trace(m_mark);
 }
 
 }  // namespace blink