TEXTAREA: Cutting last line without EOL should not remove the remaining EOL in the previous line.

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

 /*
  * Copyright (C) 2005 Apple Computer, 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 173 matching lines @@
         startPosition = positionBeforeStartNode;
     if (!isVisuallyEquivalentCandidate(startPosition))
         startPosition = mostForwardCaretPosition(startPosition);
 
     startPosition = positionAvoidingSpecialElementBoundary(startPosition, editingState);
     if (editingState->isAborted())
         return;
 
     Position endPosition;
 
-    if (m_text == "\t") {
+    if (m_text == "\t" && isRichlyEditablePosition(startPosition)) {
         endPosition = insertTab(startPosition, editingState);
         if (editingState->isAborted())
             return;
         // TODO(yosin) We should use |PositionMoveType::Character| for
         // |previousPositionOf()|.
         startPosition = previousPositionOf(endPosition, PositionMoveType::Character);
         if (placeholder.isNotNull())
             removePlaceholderAt(placeholder);
     } else {
         // Make sure the document is set up to receive m_text
@@ skipping 77 matching lines @@
         }
     }
     if (editingState->isAborted())
         return Position();
 
     // return the position following the new tab
     return lastPositionInNode(spanElement.get());
 }
 
 } // namespace blink