Fix for broken undo functionality

Source/core/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 92 matching lines @@
         lastTypingCommand->deleteSelection(options & SmartDelete);
         return;
     }
 
     TypingCommand::create(document, DeleteSelection, "", options)->apply();
 }
 
 void TypingCommand::deleteKeyPressed(Document& document, Options options, TextGranularity granularity)
 {
     if (granularity == CharacterGranularity) {
-        if (RefPtr<TypingCommand> lastTypingCommand = lastTypingCommandIfStillOpenForTyping(document.frame())) {
-            updateSelectionIfDifferentFromCurrentSelection(lastTypingCommand.get(), document.frame());
-            lastTypingCommand->setShouldPreventSpellChecking(options & PreventSpellChecking);
-            lastTypingCommand->deleteKeyPressed(granularity, options & KillRing);
-            return;
+        Frame* frame = document.frame();
+        if (RefPtr<TypingCommand> lastTypingCommand = lastTypingCommandIfStillOpenForTyping(frame)) {
+            // If the last typing command is not Delete, open a new typing command.
+            // We need to group continuous delete commands alone in a single typing command.
+            if (lastTypingCommand->commandTypeOfOpenCommand() == DeleteKey) {
+                updateSelectionIfDifferentFromCurrentSelection(lastTypingCommand.get(), frame);
+                lastTypingCommand->setShouldPreventSpellChecking(options & PreventSpellChecking);
+                lastTypingCommand->deleteKeyPressed(granularity, options & KillRing);
+                return;
+            }
         }
     }
 
     TypingCommand::create(document, DeleteKey, "", options, granularity)->apply();
 }
 
 void TypingCommand::forwardDeleteKeyPressed(Document& document, Options options, TextGranularity granularity)
 {
     // FIXME: Forward delete in TextEdit appears to open and close a new typing command.
-    Frame* frame = document.frame();
     if (granularity == CharacterGranularity) {
+        Frame* frame = document.frame();
         if (RefPtr<TypingCommand> lastTypingCommand = lastTypingCommandIfStillOpenForTyping(frame)) {
             updateSelectionIfDifferentFromCurrentSelection(lastTypingCommand.get(), frame);
             lastTypingCommand->setShouldPreventSpellChecking(options & PreventSpellChecking);
             lastTypingCommand->forwardDeleteKeyPressed(granularity, options & KillRing);
             return;
         }
     }
 
     TypingCommand::create(document, ForwardDeleteKey, "", options, granularity)->apply();
 }
@@ skipping 165 matching lines @@
     }
 }
 
 void TypingCommand::typingAddedToOpenCommand(ETypingCommand commandTypeForAddedTyping)
 {
     Frame* frame = document().frame();
     if (!frame)
         return;
 
     updatePreservesTypingStyle(commandTypeForAddedTyping);
+    updateCommandTypeOfOpenCommand(commandTypeForAddedTyping);
 
     // The old spellchecking code requires that checking be done first, to prevent issues like that in 6864072, where <doesn't> is marked as misspelled.
     markMisspellingsAfterTyping(commandTypeForAddedTyping);
     frame->editor().appliedEditing(this);
 }
 
 void TypingCommand::insertText(const String &text, bool selectInsertedText)
 {
     // FIXME: Need to implement selectInsertedText for cases where more than one insert is involved.
     // This requires support from insertTextRunWithoutNewlines and insertParagraphSeparator for extending
@@ skipping 285 matching lines @@
     ASSERT_NOT_REACHED();
     m_preservesTypingStyle = false;
 }
 
 bool TypingCommand::isTypingCommand() const
 {
     return true;
 }
 
 } // namespace WebCore