WebKit merge 40668:40722 part 1.

third_party/WebKit/WebCore/editing/TypingCommand.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 399 matching lines @@
                 selection.modify(SelectionController::EXTEND, SelectionController::BACKWARD, granularity);
             // If the caret is just after a table, select the table and don't delete anything.
             } else if (Node* table = isFirstPositionAfterTable(visibleStart)) {
                 setEndingSelection(Selection(Position(table, 0), endingSelection().start(), DOWNSTREAM));
                 typingAddedToOpenCommand();
                 return;
             }
 
             selectionToDelete = selection.selection();
 
-            if (granularity == CharacterGranularity && selectionToDelete.end().offset() - selectionToDelete.start().offset() > 1) {
-                // When we delete a ligature consisting of multiple Unicode characters with a backspace key,
-                // we should not delete the ligature but delete only its last characeter. To check we are deleting
-                // a ligature, we retrieve the previous position of the caret and count the number of
-                // characters to be deleted.
-                // To prevent from calculating the previous position every time when pressing a backspace key,
-                // we retrieve the previous position only when the given selection consists of two or more characters.
-                if (selectionToDelete.end().offset() - selectionToDelete.end().previous(UsingComposedCharacters).offset() > 1)
-                    selectionToDelete.setWithoutValidation(selectionToDelete.end(), selectionToDelete.end().previous(NotUsingComposedCharacters));
+            if (granularity == CharacterGranularity && selectionToDelete.end().node() == selectionToDelete.start().node() && selectionToDelete.end().offset() - selectionToDelete.start().offset() > 1) {
+                // If there are multiple Unicode code points to be deleted, adjust the range to match platform conventions.
+                selectionToDelete.setWithoutValidation(selectionToDelete.end(), selectionToDelete.end().previous(BackwardDeletion));
             }
 
             if (!startingSelection().isRange() || selectionToDelete.base() != startingSelection().start())
                 selectionAfterUndo = selectionToDelete;
             else
                 // It's a little tricky to compute what the starting selection would have been in the original document.
                 // We can't let the Selection class's validation kick in or it'll adjust for us based on
                 // the current state of the document and we'll get the wrong result.
                 selectionAfterUndo.setWithoutValidation(startingSelection().end(), selectionToDelete.extent());
             break;
@@ skipping 115 matching lines @@
     return false;
 }
 
 bool TypingCommand::isTypingCommand() const
 {
     return true;
 }
 
 } // namespace WebCore