Make CompositeEditCommand::moveParagraph() to abort when destination becomes invisible

third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1323 matching lines @@
         // FIXME: Trim text between beforeParagraph and afterParagraph if they aren't equal.
         insertNodeAt(HTMLBRElement::create(document()), beforeParagraph.deepEquivalent(), editingState);
         if (editingState->isAborted())
             return;
         // Need an updateLayout here in case inserting the br has split a text node.
         document().updateStyleAndLayoutIgnorePendingStylesheets();
     }
 
     destinationIndex = TextIterator::rangeLength(Position::firstPositionInNode(document().documentElement()), destination.toParentAnchoredPosition(), true);
 
-    setEndingSelection(VisibleSelection(destination, originalIsDirectional));
-    DCHECK(!endingSelection().isNone());
+    VisibleSelection destinationSelection(destination, originalIsDirectional);
+    if (endingSelection().isNone()) {
+        // We abort executing command since |destination| becomes invisible.
+        editingState->abort();
+        return;
+    }
+    setEndingSelection(destinationSelection);
     ReplaceSelectionCommand::CommandOptions options = ReplaceSelectionCommand::SelectReplacement | ReplaceSelectionCommand::MovingParagraph;
     if (shouldPreserveStyle == DoNotPreserveStyle)
         options |= ReplaceSelectionCommand::MatchStyle;
     applyCommandToComposite(ReplaceSelectionCommand::create(document(), fragment, options), editingState);
     if (editingState->isAborted())
         return;
 
     document().frame()->spellChecker().markMisspellingsAndBadGrammar(endingSelection());
 
     // If the selection is in an empty paragraph, restore styles from the old empty paragraph to the new empty paragraph.
@@ skipping 267 matching lines @@
 }
 
 DEFINE_TRACE(CompositeEditCommand)
 {
     visitor->trace(m_commands);
     visitor->trace(m_composition);
     EditCommand::trace(visitor);
 }
 
 } // namespace blink