Remove direct reads to m_firstNodeInserted and m_lastLeafInserted in ReplaceSelection...

Remove direct reads to m_firstNodeInserted and m_lastLeafInserted in ReplaceSelectionCommand
https://bugs.webkit.org/show_bug.cgi?id=69023

Reviewed by Enrica Casucci.

Converted to removeUnrenderedTextNodesAtEnds to use InsertedNodes instead of m_firstNodeInserted
and m_lastLeafInserted. Extracted the logic to update nodes as InsertedNodes::willRemoveNode
(old one was renamed to InsertedNodes::willRemoveNodePreservingChildren).

Also extracted shouldPerformSmartReplace and addSpacesForSmartReplace out of doApply,
and rewrote the logic to obtain endNode and startNode using startOfInsertedContent and
endOfInsertedContent instead of m_firstNodeInserted and m_lastLeafInserted.

Finally, replaced the nullity checks of m_firstNodeInserted and m_lastLeafInserted in
completeHTMLReplacement by nullity checks of start and end positions.

* dom/Node.cpp:
(WebCore::Node::traversePreviousSibling): Added.
* dom/Node.h:
* editing/ReplaceSelectionCommand.cpp:
(WebCore::ReplaceSelectionCommand::InsertedNodes::willRemoveNodePreservingChildren): Renamed from
willRemoveNode.
(WebCore::ReplaceSelectionCommand::InsertedNodes::willRemoveNode): Extracted from
removeUnrenderedTextNodesAtEnds.
(WebCore::ReplaceSelectionCommand::removeRedundantStylesAndKeepStyleSpanInline):
(WebCore::ReplaceSelectionCommand::removeUnrenderedTextNodesAtEnds):
(WebCore::ReplaceSelectionCommand::positionAtEndOfInsertedContent): Made const.
(WebCore::ReplaceSelectionCommand::positionAtStartOfInsertedContent): Made const.
(WebCore::ReplaceSelectionCommand::handleStyleSpans): Takes firstNodeInserted instead of directly
accessing m_firstNodeInserted.
(WebCore::ReplaceSelectionCommand::doApply):
(WebCore::ReplaceSelectionCommand::shouldPerformSmartReplace):
(WebCore::ReplaceSelectionCommand::addSpacesForSmartReplace):
(WebCore::ReplaceSelectionCommand::completeHTMLReplacement):
* editing/ReplaceSelectionCommand.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@96353 268f45cc-cd09-0410-ab3c-d52691b4dbfc