Use PositionMoveType::GraphemeBoundary

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 177 matching lines @@
     startPosition = positionAvoidingSpecialElementBoundary(startPosition, editingState);
     if (editingState->isAborted())
         return;
 
     Position endPosition;
 
     if (m_text == "\t" && isRichlyEditablePosition(startPosition)) {
         endPosition = insertTab(startPosition, editingState);
         if (editingState->isAborted())
             return;
-        // TODO(yosin) We should use |PositionMoveType::CodePoint| for
-        // |previousPositionOf()|.
-        startPosition = previousPositionOf(endPosition, PositionMoveType::CodePoint);
+        startPosition = previousPositionOf(endPosition, PositionMoveType::GraphemeCluster);
         if (placeholder.isNotNull())
             removePlaceholderAt(placeholder);
     } else {
         // Make sure the document is set up to receive m_text
         startPosition = positionInsideTextNode(startPosition, editingState);
         if (editingState->isAborted())
             return;
         ASSERT(startPosition.isOffsetInAnchor());
         ASSERT(startPosition.computeContainerNode());
         ASSERT(startPosition.computeContainerNode()->isTextNode());
@@ skipping 71 matching lines @@
         }
     }
     if (editingState->isAborted())
         return Position();
 
     // return the position following the new tab
     return lastPositionInNode(spanElement.get());
 }
 
 } // namespace blink