diff -r 000000000000 -r 4f2f89ce4247 WebCore/editing/ReplaceSelectionCommand.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/editing/ReplaceSelectionCommand.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,1274 @@
+/*
+ * Copyright (C) 2005, 2006, 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
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "ReplaceSelectionCommand.h"
+
+#include "ApplyStyleCommand.h"
+#include "BeforeTextInsertedEvent.h"
+#include "BreakBlockquoteCommand.h"
+#include "CSSComputedStyleDeclaration.h"
+#include "CSSMutableStyleDeclaration.h"
+#include "CSSProperty.h"
+#include "CSSPropertyNames.h"
+#include "CSSValueKeywords.h"
+#include "Document.h"
+#include "DocumentFragment.h"
+#include "EditingText.h"
+#include "Element.h"
+#include "EventNames.h"
+#include "Frame.h"
+#include "HTMLElement.h"
+#include "HTMLInputElement.h"
+#include "HTMLInterchange.h"
+#include "HTMLNames.h"
+#include "SelectionController.h"
+#include "SmartReplace.h"
+#include "TextIterator.h"
+#include "htmlediting.h"
+#include "markup.h"
+#include "visible_units.h"
+#include <wtf/StdLibExtras.h>
+
+namespace WebCore {
+
+using namespace HTMLNames;
+
+enum EFragmentType { EmptyFragment, SingleTextNodeFragment, TreeFragment };
+
+// --- ReplacementFragment helper class
+
+class ReplacementFragment : public Noncopyable {
+public:
+    ReplacementFragment(Document*, DocumentFragment*, bool matchStyle, const VisibleSelection&);
+
+    Node* firstChild() const;
+    Node* lastChild() const;
+
+    bool isEmpty() const;
+    
+    bool hasInterchangeNewlineAtStart() const { return m_hasInterchangeNewlineAtStart; }
+    bool hasInterchangeNewlineAtEnd() const { return m_hasInterchangeNewlineAtEnd; }
+    
+    void removeNode(PassRefPtr<Node>);
+    void removeNodePreservingChildren(Node*);
+
+private:
+    PassRefPtr<Node> insertFragmentForTestRendering(Node* context);
+    void removeUnrenderedNodes(Node*);
+    void restoreTestRenderingNodesToFragment(Node*);
+    void removeInterchangeNodes(Node*);
+    
+    void insertNodeBefore(PassRefPtr<Node> node, Node* refNode);
+
+    RefPtr<Document> m_document;
+    RefPtr<DocumentFragment> m_fragment;
+    bool m_matchStyle;
+    bool m_hasInterchangeNewlineAtStart;
+    bool m_hasInterchangeNewlineAtEnd;
+};
+
+static bool isInterchangeNewlineNode(const Node *node)
+{
+    DEFINE_STATIC_LOCAL(String, interchangeNewlineClassString, (AppleInterchangeNewline));
+    return node && node->hasTagName(brTag) && 
+           static_cast<const Element *>(node)->getAttribute(classAttr) == interchangeNewlineClassString;
+}
+
+static bool isInterchangeConvertedSpaceSpan(const Node *node)
+{
+    DEFINE_STATIC_LOCAL(String, convertedSpaceSpanClassString, (AppleConvertedSpace));
+    return node->isHTMLElement() && 
+           static_cast<const HTMLElement *>(node)->getAttribute(classAttr) == convertedSpaceSpanClassString;
+}
+
+static Position positionAvoidingPrecedingNodes(Position pos)
+{
+    // If we're already on a break, it's probably a placeholder and we shouldn't change our position.
+    if (pos.node()->hasTagName(brTag))
+        return pos;
+
+    // We also stop when changing block flow elements because even though the visual position is the
+    // same.  E.g.,
+    //   <div>foo^</div>^
+    // The two positions above are the same visual position, but we want to stay in the same block.
+    Node* stopNode = pos.node()->enclosingBlockFlowElement();
+    while (stopNode != pos.node() && VisiblePosition(pos) == VisiblePosition(pos.next()))
+        pos = pos.next();
+    return pos;
+}
+
+ReplacementFragment::ReplacementFragment(Document* document, DocumentFragment* fragment, bool matchStyle, const VisibleSelection& selection)
+    : m_document(document),
+      m_fragment(fragment),
+      m_matchStyle(matchStyle), 
+      m_hasInterchangeNewlineAtStart(false), 
+      m_hasInterchangeNewlineAtEnd(false)
+{
+    if (!m_document)
+        return;
+    if (!m_fragment)
+        return;
+    if (!m_fragment->firstChild())
+        return;
+    
+    Element* editableRoot = selection.rootEditableElement();
+    ASSERT(editableRoot);
+    if (!editableRoot)
+        return;
+    
+    Node* shadowAncestorNode = editableRoot->shadowAncestorNode();
+    
+    if (!editableRoot->getAttributeEventListener(eventNames().webkitBeforeTextInsertedEvent) &&
+        // FIXME: Remove these checks once textareas and textfields actually register an event handler.
+        !(shadowAncestorNode && shadowAncestorNode->renderer() && shadowAncestorNode->renderer()->isTextControl()) &&
+        editableRoot->isContentRichlyEditable()) {
+        removeInterchangeNodes(m_fragment.get());
+        return;
+    }
+
+    Node* styleNode = selection.base().node();
+    RefPtr<Node> holder = insertFragmentForTestRendering(styleNode);
+    
+    RefPtr<Range> range = VisibleSelection::selectionFromContentsOfNode(holder.get()).toNormalizedRange();
+    String text = plainText(range.get());
+    // Give the root a chance to change the text.
+    RefPtr<BeforeTextInsertedEvent> evt = BeforeTextInsertedEvent::create(text);
+    ExceptionCode ec = 0;
+    editableRoot->dispatchEvent(evt, ec);
+    ASSERT(ec == 0);
+    if (text != evt->text() || !editableRoot->isContentRichlyEditable()) {
+        restoreTestRenderingNodesToFragment(holder.get());
+        removeNode(holder);
+
+        m_fragment = createFragmentFromText(selection.toNormalizedRange().get(), evt->text());
+        if (!m_fragment->firstChild())
+            return;
+        holder = insertFragmentForTestRendering(styleNode);
+    }
+    
+    removeInterchangeNodes(holder.get());
+    
+    removeUnrenderedNodes(holder.get());
+    restoreTestRenderingNodesToFragment(holder.get());
+    removeNode(holder);
+}
+
+bool ReplacementFragment::isEmpty() const
+{
+    return (!m_fragment || !m_fragment->firstChild()) && !m_hasInterchangeNewlineAtStart && !m_hasInterchangeNewlineAtEnd;
+}
+
+Node *ReplacementFragment::firstChild() const 
+{ 
+    return m_fragment ? m_fragment->firstChild() : 0; 
+}
+
+Node *ReplacementFragment::lastChild() const 
+{ 
+    return m_fragment ? m_fragment->lastChild() : 0; 
+}
+
+void ReplacementFragment::removeNodePreservingChildren(Node *node)
+{
+    if (!node)
+        return;
+
+    while (RefPtr<Node> n = node->firstChild()) {
+        removeNode(n);
+        insertNodeBefore(n.release(), node);
+    }
+    removeNode(node);
+}
+
+void ReplacementFragment::removeNode(PassRefPtr<Node> node)
+{
+    if (!node)
+        return;
+    
+    Node *parent = node->parentNode();
+    if (!parent)
+        return;
+    
+    ExceptionCode ec = 0;
+    parent->removeChild(node.get(), ec);
+    ASSERT(ec == 0);
+}
+
+void ReplacementFragment::insertNodeBefore(PassRefPtr<Node> node, Node* refNode)
+{
+    if (!node || !refNode)
+        return;
+        
+    Node* parent = refNode->parentNode();
+    if (!parent)
+        return;
+        
+    ExceptionCode ec = 0;
+    parent->insertBefore(node, refNode, ec);
+    ASSERT(ec == 0);
+}
+
+PassRefPtr<Node> ReplacementFragment::insertFragmentForTestRendering(Node* context)
+{
+    Node* body = m_document->body();
+    if (!body)
+        return 0;
+
+    RefPtr<StyledElement> holder = createDefaultParagraphElement(m_document.get());
+    
+    ExceptionCode ec = 0;
+
+    // Copy the whitespace and user-select style from the context onto this element.
+    // FIXME: We should examine other style properties to see if they would be appropriate to consider during the test rendering.
+    Node* n = context;
+    while (n && !n->isElementNode())
+        n = n->parentNode();
+    if (n) {
+        RefPtr<CSSComputedStyleDeclaration> conFontStyle = computedStyle(n);
+        CSSStyleDeclaration* style = holder->style();
+        style->setProperty(CSSPropertyWhiteSpace, conFontStyle->getPropertyValue(CSSPropertyWhiteSpace), false, ec);
+        ASSERT(ec == 0);
+        style->setProperty(CSSPropertyWebkitUserSelect, conFontStyle->getPropertyValue(CSSPropertyWebkitUserSelect), false, ec);
+        ASSERT(ec == 0);
+    }
+    
+    holder->appendChild(m_fragment, ec);
+    ASSERT(ec == 0);
+    
+    body->appendChild(holder.get(), ec);
+    ASSERT(ec == 0);
+    
+    m_document->updateLayoutIgnorePendingStylesheets();
+    
+    return holder.release();
+}
+
+void ReplacementFragment::restoreTestRenderingNodesToFragment(Node *holder)
+{
+    if (!holder)
+        return;
+    
+    ExceptionCode ec = 0;
+    while (RefPtr<Node> node = holder->firstChild()) {
+        holder->removeChild(node.get(), ec);
+        ASSERT(ec == 0);
+        m_fragment->appendChild(node.get(), ec);
+        ASSERT(ec == 0);
+    }
+}
+
+void ReplacementFragment::removeUnrenderedNodes(Node* holder)
+{
+    Vector<Node*> unrendered;
+
+    for (Node* node = holder->firstChild(); node; node = node->traverseNextNode(holder))
+        if (!isNodeRendered(node) && !isTableStructureNode(node))
+            unrendered.append(node);
+
+    size_t n = unrendered.size();
+    for (size_t i = 0; i < n; ++i)
+        removeNode(unrendered[i]);
+}
+
+void ReplacementFragment::removeInterchangeNodes(Node* container)
+{
+    // Interchange newlines at the "start" of the incoming fragment must be
+    // either the first node in the fragment or the first leaf in the fragment.
+    Node* node = container->firstChild();
+    while (node) {
+        if (isInterchangeNewlineNode(node)) {
+            m_hasInterchangeNewlineAtStart = true;
+            removeNode(node);
+            break;
+        }
+        node = node->firstChild();
+    }
+    if (!container->hasChildNodes())
+        return;
+    // Interchange newlines at the "end" of the incoming fragment must be
+    // either the last node in the fragment or the last leaf in the fragment.
+    node = container->lastChild();
+    while (node) {
+        if (isInterchangeNewlineNode(node)) {
+            m_hasInterchangeNewlineAtEnd = true;
+            removeNode(node);
+            break;
+        }
+        node = node->lastChild();
+    }
+    
+    node = container->firstChild();
+    while (node) {
+        Node *next = node->traverseNextNode();
+        if (isInterchangeConvertedSpaceSpan(node)) {
+            RefPtr<Node> n = 0;
+            while ((n = node->firstChild())) {
+                removeNode(n);
+                insertNodeBefore(n, node);
+            }
+            removeNode(node);
+            if (n)
+                next = n->traverseNextNode();
+        }
+        node = next;
+    }
+}
+
+ReplaceSelectionCommand::ReplaceSelectionCommand(Document* document, PassRefPtr<DocumentFragment> fragment,
+        bool selectReplacement, bool smartReplace, bool matchStyle, bool preventNesting, bool movingParagraph,
+        EditAction editAction) 
+    : CompositeEditCommand(document),
+      m_selectReplacement(selectReplacement), 
+      m_smartReplace(smartReplace),
+      m_matchStyle(matchStyle),
+      m_documentFragment(fragment),
+      m_preventNesting(preventNesting),
+      m_movingParagraph(movingParagraph),
+      m_editAction(editAction),
+      m_shouldMergeEnd(false)
+{
+}
+
+static bool hasMatchingQuoteLevel(VisiblePosition endOfExistingContent, VisiblePosition endOfInsertedContent)
+{
+    Position existing = endOfExistingContent.deepEquivalent();
+    Position inserted = endOfInsertedContent.deepEquivalent();
+    bool isInsideMailBlockquote = nearestMailBlockquote(inserted.node());
+    return isInsideMailBlockquote && (numEnclosingMailBlockquotes(existing) == numEnclosingMailBlockquotes(inserted));
+}
+
+bool ReplaceSelectionCommand::shouldMergeStart(bool selectionStartWasStartOfParagraph, bool fragmentHasInterchangeNewlineAtStart, bool selectionStartWasInsideMailBlockquote)
+{
+    if (m_movingParagraph)
+        return false;
+    
+    VisiblePosition startOfInsertedContent(positionAtStartOfInsertedContent());
+    VisiblePosition prev = startOfInsertedContent.previous(true);
+    if (prev.isNull())
+        return false;
+    
+    // When we have matching quote levels, its ok to merge more frequently.
+    // For a successful merge, we still need to make sure that the inserted content starts with the beginning of a paragraph.
+    // And we should only merge here if the selection start was inside a mail blockquote.  This prevents against removing a 
+    // blockquote from newly pasted quoted content that was pasted into an unquoted position.  If that unquoted position happens 
+    // to be right after another blockquote, we don't want to merge and risk stripping a valid block (and newline) from the pasted content.
+    if (isStartOfParagraph(startOfInsertedContent) && selectionStartWasInsideMailBlockquote && hasMatchingQuoteLevel(prev, positionAtEndOfInsertedContent()))
+        return true;
+
+    return !selectionStartWasStartOfParagraph && 
+           !fragmentHasInterchangeNewlineAtStart &&
+           isStartOfParagraph(startOfInsertedContent) && 
+           !startOfInsertedContent.deepEquivalent().node()->hasTagName(brTag) &&
+           shouldMerge(startOfInsertedContent, prev);
+}
+
+bool ReplaceSelectionCommand::shouldMergeEnd(bool selectionEndWasEndOfParagraph)
+{
+    VisiblePosition endOfInsertedContent(positionAtEndOfInsertedContent());
+    VisiblePosition next = endOfInsertedContent.next(true);
+    if (next.isNull())
+        return false;
+
+    return !selectionEndWasEndOfParagraph &&
+           isEndOfParagraph(endOfInsertedContent) && 
+           !endOfInsertedContent.deepEquivalent().node()->hasTagName(brTag) &&
+           shouldMerge(endOfInsertedContent, next);
+}
+
+static bool isMailPasteAsQuotationNode(const Node* node)
+{
+    return node && node->hasTagName(blockquoteTag) && node->isElementNode() && static_cast<const Element*>(node)->getAttribute(classAttr) == ApplePasteAsQuotation;
+}
+
+// Wrap CompositeEditCommand::removeNodePreservingChildren() so we can update the nodes we track
+void ReplaceSelectionCommand::removeNodePreservingChildren(Node* node)
+{
+    if (m_firstNodeInserted == node)
+        m_firstNodeInserted = node->traverseNextNode();
+    if (m_lastLeafInserted == node)
+        m_lastLeafInserted = node->lastChild() ? node->lastChild() : node->traverseNextSibling();
+    CompositeEditCommand::removeNodePreservingChildren(node);
+}
+
+// Wrap CompositeEditCommand::removeNodeAndPruneAncestors() so we can update the nodes we track
+void ReplaceSelectionCommand::removeNodeAndPruneAncestors(Node* node)
+{
+    // prepare in case m_firstNodeInserted and/or m_lastLeafInserted get removed
+    // FIXME: shouldn't m_lastLeafInserted be adjusted using traversePreviousNode()?
+    Node* afterFirst = m_firstNodeInserted ? m_firstNodeInserted->traverseNextSibling() : 0;
+    Node* afterLast = m_lastLeafInserted ? m_lastLeafInserted->traverseNextSibling() : 0;
+    
+    CompositeEditCommand::removeNodeAndPruneAncestors(node);
+    
+    // adjust m_firstNodeInserted and m_lastLeafInserted since either or both may have been removed
+    if (m_lastLeafInserted && !m_lastLeafInserted->inDocument())
+        m_lastLeafInserted = afterLast;
+    if (m_firstNodeInserted && !m_firstNodeInserted->inDocument())
+        m_firstNodeInserted = m_lastLeafInserted && m_lastLeafInserted->inDocument() ? afterFirst : 0;
+}
+
+static bool isHeaderElement(Node* a)
+{
+    if (!a)
+        return false;
+        
+    return a->hasTagName(h1Tag) ||
+           a->hasTagName(h2Tag) ||
+           a->hasTagName(h3Tag) ||
+           a->hasTagName(h4Tag) ||
+           a->hasTagName(h5Tag);
+}
+
+static bool haveSameTagName(Node* a, Node* b)
+{
+    return a && b && a->isElementNode() && b->isElementNode() && static_cast<Element*>(a)->tagName() == static_cast<Element*>(b)->tagName();
+}
+
+bool ReplaceSelectionCommand::shouldMerge(const VisiblePosition& source, const VisiblePosition& destination)
+{
+    if (source.isNull() || destination.isNull())
+        return false;
+        
+    Node* sourceNode = source.deepEquivalent().node();
+    Node* destinationNode = destination.deepEquivalent().node();
+    Node* sourceBlock = enclosingBlock(sourceNode);
+    Node* destinationBlock = enclosingBlock(destinationNode);
+    return !enclosingNodeOfType(source.deepEquivalent(), &isMailPasteAsQuotationNode) &&
+           sourceBlock && (!sourceBlock->hasTagName(blockquoteTag) || isMailBlockquote(sourceBlock))  &&
+           enclosingListChild(sourceBlock) == enclosingListChild(destinationNode) &&
+           enclosingTableCell(source.deepEquivalent()) == enclosingTableCell(destination.deepEquivalent()) &&
+           (!isHeaderElement(sourceBlock) || haveSameTagName(sourceBlock, destinationBlock)) &&
+           // Don't merge to or from a position before or after a block because it would
+           // be a no-op and cause infinite recursion.
+           !isBlock(sourceNode) && !isBlock(destinationNode);
+}
+
+// Style rules that match just inserted elements could change their appearance, like
+// a div inserted into a document with div { display:inline; }.
+void ReplaceSelectionCommand::negateStyleRulesThatAffectAppearance()
+{
+    for (RefPtr<Node> node = m_firstNodeInserted.get(); node; node = node->traverseNextNode()) {
+        // FIXME: <rdar://problem/5371536> Style rules that match pasted content can change it's appearance
+        if (isStyleSpan(node.get())) {
+            HTMLElement* e = static_cast<HTMLElement*>(node.get());
+            // There are other styles that style rules can give to style spans,
+            // but these are the two important ones because they'll prevent
+            // inserted content from appearing in the right paragraph.
+            // FIXME: Hyatt is concerned that selectively using display:inline will give inconsistent
+            // results. We already know one issue because td elements ignore their display property
+            // in quirks mode (which Mail.app is always in). We should look for an alternative.
+            if (isBlock(e))
+                e->getInlineStyleDecl()->setProperty(CSSPropertyDisplay, CSSValueInline);
+            if (e->renderer() && e->renderer()->style()->floating() != FNONE)
+                e->getInlineStyleDecl()->setProperty(CSSPropertyFloat, CSSValueNone);
+
+            // Undo the effects of page zoom if we have an absolute font size.  When we copy, we
+            // compute the new font size as an absolute size so pasting will cause the zoom to be
+            // applied twice.
+            if (e->renderer() && e->renderer()->style() && e->renderer()->style()->effectiveZoom() != 1.0
+                && e->renderer()->style()->fontDescription().isAbsoluteSize()) {
+                float newSize = e->renderer()->style()->fontDescription().specifiedSize() / e->renderer()->style()->effectiveZoom();
+                ExceptionCode ec = 0;
+                e->style()->setProperty(CSSPropertyFontSize, String::number(newSize), false, ec);
+                ASSERT(!ec);
+            }
+        }
+        if (node == m_lastLeafInserted)
+            break;
+    }
+}
+
+void ReplaceSelectionCommand::removeUnrenderedTextNodesAtEnds()
+{
+    document()->updateLayoutIgnorePendingStylesheets();
+    if (!m_lastLeafInserted->renderer() && 
+        m_lastLeafInserted->isTextNode() && 
+        !enclosingNodeWithTag(Position(m_lastLeafInserted.get(), 0), selectTag) && 
+        !enclosingNodeWithTag(Position(m_lastLeafInserted.get(), 0), scriptTag)) {
+        if (m_firstNodeInserted == m_lastLeafInserted) {
+            removeNode(m_lastLeafInserted.get());
+            m_lastLeafInserted = 0;
+            m_firstNodeInserted = 0;
+            return;
+        }
+        RefPtr<Node> previous = m_lastLeafInserted->traversePreviousNode();
+        removeNode(m_lastLeafInserted.get());
+        m_lastLeafInserted = previous;
+    }
+    
+    // We don't have to make sure that m_firstNodeInserted isn't inside a select or script element, because
+    // it is a top level node in the fragment and the user can't insert into those elements.
+    if (!m_firstNodeInserted->renderer() && 
+        m_firstNodeInserted->isTextNode()) {
+        if (m_firstNodeInserted == m_lastLeafInserted) {
+            removeNode(m_firstNodeInserted.get());
+            m_firstNodeInserted = 0;
+            m_lastLeafInserted = 0;
+            return;
+        }
+        RefPtr<Node> next = m_firstNodeInserted->traverseNextSibling();
+        removeNode(m_firstNodeInserted.get());
+        m_firstNodeInserted = next;
+    }
+}
+
+void ReplaceSelectionCommand::handlePasteAsQuotationNode()
+{
+    Node* node = m_firstNodeInserted.get();
+    if (isMailPasteAsQuotationNode(node))
+        removeNodeAttribute(static_cast<Element*>(node), classAttr);
+}
+
+VisiblePosition ReplaceSelectionCommand::positionAtEndOfInsertedContent()
+{
+    Node* lastNode = m_lastLeafInserted.get();
+    // FIXME: Why is this hack here?  What's special about <select> tags?
+    Node* enclosingSelect = enclosingNodeWithTag(firstDeepEditingPositionForNode(lastNode), selectTag);
+    if (enclosingSelect)
+        lastNode = enclosingSelect;
+    return lastDeepEditingPositionForNode(lastNode);
+}
+
+VisiblePosition ReplaceSelectionCommand::positionAtStartOfInsertedContent()
+{
+    // Return the inserted content's first VisiblePosition.
+    return VisiblePosition(nextCandidate(positionInParentBeforeNode(m_firstNodeInserted.get())));
+}
+
+// Remove style spans before insertion if they are unnecessary.  It's faster because we'll 
+// avoid doing a layout.
+static bool handleStyleSpansBeforeInsertion(ReplacementFragment& fragment, const Position& insertionPos)
+{
+    Node* topNode = fragment.firstChild();
+    
+    // Handling the case where we are doing Paste as Quotation or pasting into quoted content is more complicated (see handleStyleSpans)
+    // and doesn't receive the optimization.
+    if (isMailPasteAsQuotationNode(topNode) || nearestMailBlockquote(topNode))
+        return false;
+    
+    // Either there are no style spans in the fragment or a WebKit client has added content to the fragment
+    // before inserting it.  Look for and handle style spans after insertion.
+    if (!isStyleSpan(topNode))
+        return false;
+    
+    Node* sourceDocumentStyleSpan = topNode;
+    RefPtr<Node> copiedRangeStyleSpan = sourceDocumentStyleSpan->firstChild();
+
+    RefPtr<CSSMutableStyleDeclaration> styleAtInsertionPos = ApplyStyleCommand::editingStyleAtPosition(rangeCompliantEquivalent(insertionPos));
+
+    String styleText = styleAtInsertionPos->cssText();
+    
+    if (styleText == static_cast<Element*>(sourceDocumentStyleSpan)->getAttribute(styleAttr)) {
+        fragment.removeNodePreservingChildren(sourceDocumentStyleSpan);
+        if (!isStyleSpan(copiedRangeStyleSpan.get()))
+            return true;
+    }
+        
+    if (isStyleSpan(copiedRangeStyleSpan.get()) && styleText == static_cast<Element*>(copiedRangeStyleSpan.get())->getAttribute(styleAttr)) {
+        fragment.removeNodePreservingChildren(copiedRangeStyleSpan.get());
+        return true;
+    }
+    
+    return false;
+}
+
+// At copy time, WebKit wraps copied content in a span that contains the source document's 
+// default styles.  If the copied Range inherits any other styles from its ancestors, we put 
+// those styles on a second span.
+// This function removes redundant styles from those spans, and removes the spans if all their 
+// styles are redundant. 
+// We should remove the Apple-style-span class when we're done, see <rdar://problem/5685600>.
+// We should remove styles from spans that are overridden by all of their children, either here
+// or at copy time.
+void ReplaceSelectionCommand::handleStyleSpans()
+{
+    Node* sourceDocumentStyleSpan = 0;
+    Node* copiedRangeStyleSpan = 0;
+    // The style span that contains the source document's default style should be at
+    // the top of the fragment, but Mail sometimes adds a wrapper (for Paste As Quotation),
+    // so search for the top level style span instead of assuming it's at the top.
+    for (Node* node = m_firstNodeInserted.get(); node; node = node->traverseNextNode()) {
+        if (isStyleSpan(node)) {
+            sourceDocumentStyleSpan = node;
+            // If the copied Range's common ancestor had user applied inheritable styles
+            // on it, they'll be on a second style span, just below the one that holds the 
+            // document defaults.
+            if (isStyleSpan(node->firstChild()))
+                copiedRangeStyleSpan = node->firstChild();
+            break;
+        }
+    }
+    
+    // There might not be any style spans if we're pasting from another application or if 
+    // we are here because of a document.execCommand("InsertHTML", ...) call.
+    if (!sourceDocumentStyleSpan)
+        return;
+        
+    RefPtr<CSSMutableStyleDeclaration> sourceDocumentStyle = static_cast<HTMLElement*>(sourceDocumentStyleSpan)->getInlineStyleDecl()->copy();
+    Node* context = sourceDocumentStyleSpan->parentNode();
+    
+    // If Mail wraps the fragment with a Paste as Quotation blockquote, or if you're pasting into a quoted region,
+    // styles from blockquoteNode are allowed to override those from the source document, see <rdar://problem/4930986> and <rdar://problem/5089327>.
+    Node* blockquoteNode = isMailPasteAsQuotationNode(context) ? context : nearestMailBlockquote(context);
+    if (blockquoteNode) {
+        RefPtr<CSSMutableStyleDeclaration> blockquoteStyle = ApplyStyleCommand::editingStyleAtPosition(Position(blockquoteNode, 0));
+        RefPtr<CSSMutableStyleDeclaration> parentStyle = ApplyStyleCommand::editingStyleAtPosition(Position(blockquoteNode->parentNode(), 0));
+        parentStyle->diff(blockquoteStyle.get());
+
+        CSSMutableStyleDeclaration::const_iterator end = blockquoteStyle->end();
+        for (CSSMutableStyleDeclaration::const_iterator it = blockquoteStyle->begin(); it != end; ++it) {
+            const CSSProperty& property = *it;
+            sourceDocumentStyle->removeProperty(property.id());
+        }        
+
+        context = blockquoteNode->parentNode();
+    }
+
+    // This operation requires that only editing styles to be removed from sourceDocumentStyle.
+    prepareEditingStyleToApplyAt(sourceDocumentStyle.get(), Position(context, 0));
+
+    // Remove block properties in the span's style. This prevents properties that probably have no effect 
+    // currently from affecting blocks later if the style is cloned for a new block element during a future 
+    // editing operation.
+    // FIXME: They *can* have an effect currently if blocks beneath the style span aren't individually marked
+    // with block styles by the editing engine used to style them.  WebKit doesn't do this, but others might.
+    sourceDocumentStyle->removeBlockProperties();
+    
+    // The styles on sourceDocumentStyleSpan are all redundant, and there is no copiedRangeStyleSpan
+    // to consider.  We're finished.
+    if (sourceDocumentStyle->length() == 0 && !copiedRangeStyleSpan) {
+        removeNodePreservingChildren(sourceDocumentStyleSpan);
+        return;
+    }
+    
+    // There are non-redundant styles on sourceDocumentStyleSpan, but there is no
+    // copiedRangeStyleSpan.  Remove the span, because it could be surrounding block elements,
+    // and apply the styles to its children.
+    if (sourceDocumentStyle->length() > 0 && !copiedRangeStyleSpan) {
+        copyStyleToChildren(sourceDocumentStyleSpan, sourceDocumentStyle.get()); 
+        removeNodePreservingChildren(sourceDocumentStyleSpan);
+        return;
+    }
+    
+    RefPtr<CSSMutableStyleDeclaration> copiedRangeStyle = static_cast<HTMLElement*>(copiedRangeStyleSpan)->getInlineStyleDecl()->copy();
+    
+    // We're going to put sourceDocumentStyleSpan's non-redundant styles onto copiedRangeStyleSpan,
+    // as long as they aren't overridden by ones on copiedRangeStyleSpan.
+    sourceDocumentStyle->merge(copiedRangeStyle.get(), true);
+    copiedRangeStyle = sourceDocumentStyle;
+    
+    removeNodePreservingChildren(sourceDocumentStyleSpan);
+    
+    // Remove redundant styles.
+    context = copiedRangeStyleSpan->parentNode();
+    prepareEditingStyleToApplyAt(copiedRangeStyle.get(), Position(context, 0));
+
+    // See the comments above about removing block properties.
+    copiedRangeStyle->removeBlockProperties();
+
+    // All the styles on copiedRangeStyleSpan are redundant, remove it.
+    if (copiedRangeStyle->length() == 0) {
+        removeNodePreservingChildren(copiedRangeStyleSpan);
+        return;
+    }
+    
+    // Clear the redundant styles from the span's style attribute.
+    // FIXME: If font-family:-webkit-monospace is non-redundant, then the font-size should stay, even if it
+    // appears redundant.
+    setNodeAttribute(static_cast<Element*>(copiedRangeStyleSpan), styleAttr, copiedRangeStyle->cssText());
+}
+
+// Take the style attribute of a span and apply it to it's children instead.  This allows us to
+// convert invalid HTML where a span contains block elements into valid HTML while preserving
+// styles.
+void ReplaceSelectionCommand::copyStyleToChildren(Node* parentNode, const CSSMutableStyleDeclaration* parentStyle)
+{
+    ASSERT(parentNode->hasTagName(spanTag));
+    for (Node* childNode = parentNode->firstChild(); childNode; childNode = childNode->nextSibling()) {
+        if (childNode->isTextNode() || !isBlock(childNode) || childNode->hasTagName(preTag)) {
+            // In this case, put a span tag around the child node.
+            RefPtr<Node> newSpan = parentNode->cloneNode(false);
+            setNodeAttribute(static_cast<Element*>(newSpan.get()), styleAttr, parentStyle->cssText());
+            insertNodeAfter(newSpan, childNode);
+            ExceptionCode ec = 0;
+            newSpan->appendChild(childNode, ec);
+            ASSERT(!ec);
+            childNode = newSpan.get();
+        } else if (childNode->isHTMLElement()) {
+            // Copy the style attribute and merge them into the child node.  We don't want to override
+            // existing styles, so don't clobber on merge.
+            RefPtr<CSSMutableStyleDeclaration> newStyle = parentStyle->copy();
+            HTMLElement* childElement = static_cast<HTMLElement*>(childNode);
+            RefPtr<CSSMutableStyleDeclaration> existingStyles = childElement->getInlineStyleDecl()->copy();
+            existingStyles->merge(newStyle.get(), false);
+            setNodeAttribute(childElement, styleAttr, existingStyles->cssText());
+        }
+    }
+}
+
+void ReplaceSelectionCommand::mergeEndIfNeeded()
+{
+    if (!m_shouldMergeEnd)
+        return;
+
+    VisiblePosition startOfInsertedContent(positionAtStartOfInsertedContent());
+    VisiblePosition endOfInsertedContent(positionAtEndOfInsertedContent());
+    
+    // Bail to avoid infinite recursion.
+    if (m_movingParagraph) {
+        ASSERT_NOT_REACHED();
+        return;
+    }
+    
+    // Merging two paragraphs will destroy the moved one's block styles.  Always move the end of inserted forward 
+    // to preserve the block style of the paragraph already in the document, unless the paragraph to move would 
+    // include the what was the start of the selection that was pasted into, so that we preserve that paragraph's
+    // block styles.
+    bool mergeForward = !(inSameParagraph(startOfInsertedContent, endOfInsertedContent) && !isStartOfParagraph(startOfInsertedContent));
+    
+    VisiblePosition destination = mergeForward ? endOfInsertedContent.next() : endOfInsertedContent;
+    VisiblePosition startOfParagraphToMove = mergeForward ? startOfParagraph(endOfInsertedContent) : endOfInsertedContent.next();
+   
+    // Merging forward could result in deleting the destination anchor node.
+    // To avoid this, we add a placeholder node before the start of the paragraph.
+    if (endOfParagraph(startOfParagraphToMove) == destination) {
+        RefPtr<Node> placeholder = createBreakElement(document());
+        insertNodeBefore(placeholder, startOfParagraphToMove.deepEquivalent().node());
+        destination = VisiblePosition(Position(placeholder.get(), 0));
+    }
+
+    moveParagraph(startOfParagraphToMove, endOfParagraph(startOfParagraphToMove), destination);
+    
+    // Merging forward will remove m_lastLeafInserted from the document.
+    // FIXME: Maintain positions for the start and end of inserted content instead of keeping nodes.  The nodes are
+    // only ever used to create positions where inserted content starts/ends.  Also, we sometimes insert content
+    // directly into text nodes already in the document, in which case tracking inserted nodes is inadequate.
+    if (mergeForward) {
+        m_lastLeafInserted = destination.previous().deepEquivalent().node();
+        if (!m_firstNodeInserted->inDocument())
+            m_firstNodeInserted = endingSelection().visibleStart().deepEquivalent().node();
+        // If we merged text nodes, m_lastLeafInserted could be null. If this is the case,
+        // we use m_firstNodeInserted.
+        if (!m_lastLeafInserted)
+            m_lastLeafInserted = m_firstNodeInserted;
+    }
+}
+
+void ReplaceSelectionCommand::doApply()
+{
+    VisibleSelection selection = endingSelection();
+    ASSERT(selection.isCaretOrRange());
+    ASSERT(selection.start().node());
+    if (selection.isNone() || !selection.start().node())
+        return;
+    
+    bool selectionIsPlainText = !selection.isContentRichlyEditable();
+    
+    Element* currentRoot = selection.rootEditableElement();
+    ReplacementFragment fragment(document(), m_documentFragment.get(), m_matchStyle, selection);
+    
+    if (performTrivialReplace(fragment))
+        return;
+    
+    if (m_matchStyle)
+        m_insertionStyle = ApplyStyleCommand::editingStyleAtPosition(selection.start(), IncludeTypingStyle);
+    
+    VisiblePosition visibleStart = selection.visibleStart();
+    VisiblePosition visibleEnd = selection.visibleEnd();
+    
+    bool selectionEndWasEndOfParagraph = isEndOfParagraph(visibleEnd);
+    bool selectionStartWasStartOfParagraph = isStartOfParagraph(visibleStart);
+    
+    Node* startBlock = enclosingBlock(visibleStart.deepEquivalent().node());
+    
+    Position insertionPos = selection.start();
+    bool startIsInsideMailBlockquote = nearestMailBlockquote(insertionPos.node());
+    
+    if ((selectionStartWasStartOfParagraph && selectionEndWasEndOfParagraph && !startIsInsideMailBlockquote) ||
+        startBlock == currentRoot || isListItem(startBlock) || selectionIsPlainText)
+        m_preventNesting = false;
+    
+    if (selection.isRange()) {
+        // When the end of the selection being pasted into is at the end of a paragraph, and that selection
+        // spans multiple blocks, not merging may leave an empty line.
+        // When the start of the selection being pasted into is at the start of a block, not merging 
+        // will leave hanging block(s).
+        // Merge blocks if the start of the selection was in a Mail blockquote, since we handle  
+        // that case specially to prevent nesting. 
+        bool mergeBlocksAfterDelete = startIsInsideMailBlockquote || isEndOfParagraph(visibleEnd) || isStartOfBlock(visibleStart);
+        // FIXME: We should only expand to include fully selected special elements if we are copying a 
+        // selection and pasting it on top of itself.
+        deleteSelection(false, mergeBlocksAfterDelete, true, false);
+        visibleStart = endingSelection().visibleStart();
+        if (fragment.hasInterchangeNewlineAtStart()) {
+            if (isEndOfParagraph(visibleStart) && !isStartOfParagraph(visibleStart)) {
+                if (!isEndOfDocument(visibleStart))
+                    setEndingSelection(visibleStart.next());
+            } else
+                insertParagraphSeparator();
+        }
+        insertionPos = endingSelection().start();
+    } else {
+        ASSERT(selection.isCaret());
+        if (fragment.hasInterchangeNewlineAtStart()) {
+            VisiblePosition next = visibleStart.next(true);
+            if (isEndOfParagraph(visibleStart) && !isStartOfParagraph(visibleStart) && next.isNotNull())
+                setEndingSelection(next);
+            else 
+                insertParagraphSeparator();
+        }
+        // We split the current paragraph in two to avoid nesting the blocks from the fragment inside the current block.
+        // For example paste <div>foo</div><div>bar</div><div>baz</div> into <div>x^x</div>, where ^ is the caret.  
+        // As long as the  div styles are the same, visually you'd expect: <div>xbar</div><div>bar</div><div>bazx</div>, 
+        // not <div>xbar<div>bar</div><div>bazx</div></div>.
+        // Don't do this if the selection started in a Mail blockquote.
+        if (m_preventNesting && !startIsInsideMailBlockquote && !isEndOfParagraph(visibleStart) && !isStartOfParagraph(visibleStart)) {
+            insertParagraphSeparator();
+            setEndingSelection(endingSelection().visibleStart().previous());
+        }
+        insertionPos = endingSelection().start();
+    }
+    
+    // We don't want any of the pasted content to end up nested in a Mail blockquote, so first break 
+    // out of any surrounding Mail blockquotes. Unless we're inserting in a table, in which case
+    // breaking the blockquote will prevent the content from actually being inserted in the table.
+    if (startIsInsideMailBlockquote && m_preventNesting && !(enclosingNodeOfType(insertionPos, &isTableStructureNode))) { 
+        applyCommandToComposite(BreakBlockquoteCommand::create(document())); 
+        // This will leave a br between the split. 
+        Node* br = endingSelection().start().node(); 
+        ASSERT(br->hasTagName(brTag)); 
+        // Insert content between the two blockquotes, but remove the br (since it was just a placeholder). 
+        insertionPos = positionInParentBeforeNode(br);
+        removeNode(br);
+    }
+    
+    // Inserting content could cause whitespace to collapse, e.g. inserting <div>foo</div> into hello^ world.
+    prepareWhitespaceAtPositionForSplit(insertionPos);
+    
+    // NOTE: This would be an incorrect usage of downstream() if downstream() were changed to mean the last position after 
+    // p that maps to the same visible position as p (since in the case where a br is at the end of a block and collapsed 
+    // away, there are positions after the br which map to the same visible position as [br, 0]).  
+    Node* endBR = insertionPos.downstream().node()->hasTagName(brTag) ? insertionPos.downstream().node() : 0;
+    VisiblePosition originalVisPosBeforeEndBR;
+    if (endBR)
+        originalVisPosBeforeEndBR = VisiblePosition(endBR, 0, DOWNSTREAM).previous();
+    
+    startBlock = enclosingBlock(insertionPos.node());
+    
+    // Adjust insertionPos to prevent nesting.
+    // If the start was in a Mail blockquote, we will have already handled adjusting insertionPos above.
+    if (m_preventNesting && startBlock && !startIsInsideMailBlockquote) {
+        ASSERT(startBlock != currentRoot);
+        VisiblePosition visibleInsertionPos(insertionPos);
+        if (isEndOfBlock(visibleInsertionPos) && !(isStartOfBlock(visibleInsertionPos) && fragment.hasInterchangeNewlineAtEnd()))
+            insertionPos = positionInParentAfterNode(startBlock);
+        else if (isStartOfBlock(visibleInsertionPos))
+            insertionPos = positionInParentBeforeNode(startBlock);
+    }
+
+    // Paste into run of tabs splits the tab span.
+    insertionPos = positionOutsideTabSpan(insertionPos);
+    
+    // Paste at start or end of link goes outside of link.
+    insertionPos = positionAvoidingSpecialElementBoundary(insertionPos);
+    
+    // FIXME: Can this wait until after the operation has been performed?  There doesn't seem to be
+    // any work performed after this that queries or uses the typing style.
+    if (Frame* frame = document()->frame())
+        frame->clearTypingStyle();
+    
+    bool handledStyleSpans = handleStyleSpansBeforeInsertion(fragment, insertionPos);
+
+    // We don't want the destination to end up inside nodes that weren't selected.  To avoid that, we move the
+    // position forward without changing the visible position so we're still at the same visible location, but
+    // outside of preceding tags.
+    insertionPos = positionAvoidingPrecedingNodes(insertionPos);
+
+    // FIXME: When pasting rich content we're often prevented from heading down the fast path by style spans.  Try
+    // again here if they've been removed.
+    
+    // We're finished if there is nothing to add.
+    if (fragment.isEmpty() || !fragment.firstChild())
+        return;
+    
+    // 1) Insert the content.
+    // 2) Remove redundant styles and style tags, this inner <b> for example: <b>foo <b>bar</b> baz</b>.
+    // 3) Merge the start of the added content with the content before the position being pasted into.
+    // 4) Do one of the following: a) expand the last br if the fragment ends with one and it collapsed,
+    // b) merge the last paragraph of the incoming fragment with the paragraph that contained the 
+    // end of the selection that was pasted into, or c) handle an interchange newline at the end of the 
+    // incoming fragment.
+    // 5) Add spaces for smart replace.
+    // 6) Select the replacement if requested, and match style if requested.
+    
+    VisiblePosition startOfInsertedContent, endOfInsertedContent;
+    
+    RefPtr<Node> refNode = fragment.firstChild();
+    RefPtr<Node> node = refNode->nextSibling();
+    
+    fragment.removeNode(refNode);
+
+    Node* blockStart = enclosingBlock(insertionPos.node());
+    if ((isListElement(refNode.get()) || (isStyleSpan(refNode.get()) && isListElement(refNode->firstChild())))
+        && blockStart->renderer()->isListItem())
+        refNode = insertAsListItems(refNode, blockStart, insertionPos);
+    else
+        insertNodeAtAndUpdateNodesInserted(refNode, insertionPos);
+
+    // Mutation events (bug 22634) may have already removed the inserted content
+    if (!refNode->inDocument())
+        return;
+
+    bool plainTextFragment = isPlainTextMarkup(refNode.get());
+
+    while (node) {
+        Node* next = node->nextSibling();
+        fragment.removeNode(node);
+        insertNodeAfterAndUpdateNodesInserted(node, refNode.get());
+
+        // Mutation events (bug 22634) may have already removed the inserted content
+        if (!node->inDocument())
+            return;
+
+        refNode = node;
+        if (node && plainTextFragment)
+            plainTextFragment = isPlainTextMarkup(node.get());
+        node = next;
+    }
+    
+    removeUnrenderedTextNodesAtEnds();
+    
+    negateStyleRulesThatAffectAppearance();
+    
+    if (!handledStyleSpans)
+        handleStyleSpans();
+    
+    // Mutation events (bug 20161) may have already removed the inserted content
+    if (!m_firstNodeInserted || !m_firstNodeInserted->inDocument())
+        return;
+    
+    endOfInsertedContent = positionAtEndOfInsertedContent();
+    startOfInsertedContent = positionAtStartOfInsertedContent();
+    
+    // We inserted before the startBlock to prevent nesting, and the content before the startBlock wasn't in its own block and
+    // didn't have a br after it, so the inserted content ended up in the same paragraph.
+    if (startBlock && insertionPos.node() == startBlock->parentNode() && (unsigned)insertionPos.deprecatedEditingOffset() < startBlock->nodeIndex() && !isStartOfParagraph(startOfInsertedContent))
+        insertNodeAt(createBreakElement(document()).get(), startOfInsertedContent.deepEquivalent());
+    
+    Position lastPositionToSelect;
+    
+    bool interchangeNewlineAtEnd = fragment.hasInterchangeNewlineAtEnd();
+
+    if (endBR && (plainTextFragment || shouldRemoveEndBR(endBR, originalVisPosBeforeEndBR)))
+        removeNodeAndPruneAncestors(endBR);
+    
+    // Determine whether or not we should merge the end of inserted content with what's after it before we do
+    // the start merge so that the start merge doesn't effect our decision.
+    m_shouldMergeEnd = shouldMergeEnd(selectionEndWasEndOfParagraph);
+    
+    if (shouldMergeStart(selectionStartWasStartOfParagraph, fragment.hasInterchangeNewlineAtStart(), startIsInsideMailBlockquote)) {
+        VisiblePosition destination = startOfInsertedContent.previous();
+        VisiblePosition startOfParagraphToMove = startOfInsertedContent;
+        
+        // Merging the the first paragraph of inserted content with the content that came
+        // before the selection that was pasted into would also move content after 
+        // the selection that was pasted into if: only one paragraph was being pasted, 
+        // and it was not wrapped in a block, the selection that was pasted into ended 
+        // at the end of a block and the next paragraph didn't start at the start of a block.
+        // Insert a line break just after the inserted content to separate it from what 
+        // comes after and prevent that from happening.
+        VisiblePosition endOfInsertedContent = positionAtEndOfInsertedContent();
+        if (startOfParagraph(endOfInsertedContent) == startOfParagraphToMove) {
+            insertNodeAt(createBreakElement(document()).get(), endOfInsertedContent.deepEquivalent());
+            // Mutation events (bug 22634) triggered by inserting the <br> might have removed the content we're about to move
+            if (!startOfParagraphToMove.deepEquivalent().node()->inDocument())
+                return;
+        }
+
+        // FIXME: Maintain positions for the start and end of inserted content instead of keeping nodes.  The nodes are
+        // only ever used to create positions where inserted content starts/ends.
+        moveParagraph(startOfParagraphToMove, endOfParagraph(startOfParagraphToMove), destination);
+        m_firstNodeInserted = endingSelection().visibleStart().deepEquivalent().downstream().node();
+        if (!m_lastLeafInserted->inDocument())
+            m_lastLeafInserted = endingSelection().visibleEnd().deepEquivalent().upstream().node();
+    }
+            
+    endOfInsertedContent = positionAtEndOfInsertedContent();
+    startOfInsertedContent = positionAtStartOfInsertedContent();
+    
+    if (interchangeNewlineAtEnd) {
+        VisiblePosition next = endOfInsertedContent.next(true);
+
+        if (selectionEndWasEndOfParagraph || !isEndOfParagraph(endOfInsertedContent) || next.isNull()) {
+            if (!isStartOfParagraph(endOfInsertedContent)) {
+                setEndingSelection(endOfInsertedContent);
+                Node* enclosingNode = enclosingBlock(endOfInsertedContent.deepEquivalent().node());
+                if (isListItem(enclosingNode)) {
+                    RefPtr<Node> newListItem = createListItemElement(document());
+                    insertNodeAfter(newListItem, enclosingNode);
+                    setEndingSelection(VisiblePosition(Position(newListItem, 0)));
+                } else
+                    // Use a default paragraph element (a plain div) for the empty paragraph, using the last paragraph
+                    // block's style seems to annoy users.
+                    insertParagraphSeparator(true);
+
+                // Select up to the paragraph separator that was added.
+                lastPositionToSelect = endingSelection().visibleStart().deepEquivalent();
+                updateNodesInserted(lastPositionToSelect.node());
+            }
+        } else {
+            // Select up to the beginning of the next paragraph.
+            lastPositionToSelect = next.deepEquivalent().downstream();
+        }
+        
+    } else
+        mergeEndIfNeeded();
+    
+    handlePasteAsQuotationNode();
+    
+    endOfInsertedContent = positionAtEndOfInsertedContent();
+    startOfInsertedContent = positionAtStartOfInsertedContent();
+    
+    // Add spaces for smart replace.
+    if (m_smartReplace && currentRoot) {
+        // Disable smart replace for password fields.
+        Node* start = currentRoot->shadowAncestorNode();
+        if (start->hasTagName(inputTag) && static_cast<HTMLInputElement*>(start)->inputType() == HTMLInputElement::PASSWORD)
+            m_smartReplace = false;
+    }
+    if (m_smartReplace) {
+        bool needsTrailingSpace = !isEndOfParagraph(endOfInsertedContent) &&
+                                  !isCharacterSmartReplaceExempt(endOfInsertedContent.characterAfter(), false);
+        if (needsTrailingSpace) {
+            RenderObject* renderer = m_lastLeafInserted->renderer();
+            bool collapseWhiteSpace = !renderer || renderer->style()->collapseWhiteSpace();
+            Node* endNode = positionAtEndOfInsertedContent().deepEquivalent().upstream().node();
+            if (endNode->isTextNode()) {
+                Text* text = static_cast<Text*>(endNode);
+                insertTextIntoNode(text, text->length(), collapseWhiteSpace ? nonBreakingSpaceString() : " ");
+            } else {
+                RefPtr<Node> node = document()->createEditingTextNode(collapseWhiteSpace ? nonBreakingSpaceString() : " ");
+                insertNodeAfterAndUpdateNodesInserted(node, endNode);
+            }
+        }
+    
+        bool needsLeadingSpace = !isStartOfParagraph(startOfInsertedContent) &&
+                                 !isCharacterSmartReplaceExempt(startOfInsertedContent.previous().characterAfter(), true);
+        if (needsLeadingSpace) {
+            RenderObject* renderer = m_lastLeafInserted->renderer();
+            bool collapseWhiteSpace = !renderer || renderer->style()->collapseWhiteSpace();
+            Node* startNode = positionAtStartOfInsertedContent().deepEquivalent().downstream().node();
+            if (startNode->isTextNode()) {
+                Text* text = static_cast<Text*>(startNode);
+                insertTextIntoNode(text, 0, collapseWhiteSpace ? nonBreakingSpaceString() : " ");
+            } else {
+                RefPtr<Node> node = document()->createEditingTextNode(collapseWhiteSpace ? nonBreakingSpaceString() : " ");
+                // Don't updateNodesInserted.  Doing so would set m_lastLeafInserted to be the node containing the 
+                // leading space, but m_lastLeafInserted is supposed to mark the end of pasted content.
+                insertNodeBefore(node, startNode);
+                // FIXME: Use positions to track the start/end of inserted content.
+                m_firstNodeInserted = node;
+            }
+        }
+    }
+    
+    // If we are dealing with a fragment created from plain text
+    // no style matching is necessary.
+    if (plainTextFragment)
+        m_matchStyle = false;
+        
+    completeHTMLReplacement(lastPositionToSelect);
+}
+
+bool ReplaceSelectionCommand::shouldRemoveEndBR(Node* endBR, const VisiblePosition& originalVisPosBeforeEndBR)
+{
+    if (!endBR || !endBR->inDocument())
+        return false;
+        
+    VisiblePosition visiblePos(Position(endBR, 0));
+    
+    // Don't remove the br if nothing was inserted.
+    if (visiblePos.previous() == originalVisPosBeforeEndBR)
+        return false;
+    
+    // Remove the br if it is collapsed away and so is unnecessary.
+    if (!document()->inStrictMode() && isEndOfBlock(visiblePos) && !isStartOfParagraph(visiblePos))
+        return true;
+        
+    // A br that was originally holding a line open should be displaced by inserted content or turned into a line break.
+    // A br that was originally acting as a line break should still be acting as a line break, not as a placeholder.
+    return isStartOfParagraph(visiblePos) && isEndOfParagraph(visiblePos);
+}
+
+void ReplaceSelectionCommand::completeHTMLReplacement(const Position &lastPositionToSelect)
+{
+    Position start;
+    Position end;
+
+    // FIXME: This should never not be the case.
+    if (m_firstNodeInserted && m_firstNodeInserted->inDocument() && m_lastLeafInserted && m_lastLeafInserted->inDocument()) {
+        
+        start = positionAtStartOfInsertedContent().deepEquivalent();
+        end = positionAtEndOfInsertedContent().deepEquivalent();
+        
+        // FIXME (11475): Remove this and require that the creator of the fragment to use nbsps.
+        rebalanceWhitespaceAt(start);
+        rebalanceWhitespaceAt(end);
+
+        if (m_matchStyle) {
+            ASSERT(m_insertionStyle);
+            applyStyle(m_insertionStyle.get(), start, end);
+        }    
+        
+        if (lastPositionToSelect.isNotNull())
+            end = lastPositionToSelect;
+    } else if (lastPositionToSelect.isNotNull())
+        start = end = lastPositionToSelect;
+    else
+        return;
+    
+    if (m_selectReplacement)
+        setEndingSelection(VisibleSelection(start, end, SEL_DEFAULT_AFFINITY));
+    else
+        setEndingSelection(VisibleSelection(end, SEL_DEFAULT_AFFINITY));
+}
+
+EditAction ReplaceSelectionCommand::editingAction() const
+{
+    return m_editAction;
+}
+
+void ReplaceSelectionCommand::insertNodeAfterAndUpdateNodesInserted(PassRefPtr<Node> insertChild, Node* refChild)
+{
+    Node* nodeToUpdate = insertChild.get(); // insertChild will be cleared when passed
+    insertNodeAfter(insertChild, refChild);
+    updateNodesInserted(nodeToUpdate);
+}
+
+void ReplaceSelectionCommand::insertNodeAtAndUpdateNodesInserted(PassRefPtr<Node> insertChild, const Position& p)
+{
+    Node* nodeToUpdate = insertChild.get(); // insertChild will be cleared when passed
+    insertNodeAt(insertChild, p);
+    updateNodesInserted(nodeToUpdate);
+}
+
+void ReplaceSelectionCommand::insertNodeBeforeAndUpdateNodesInserted(PassRefPtr<Node> insertChild, Node* refChild)
+{
+    Node* nodeToUpdate = insertChild.get(); // insertChild will be cleared when passed
+    insertNodeBefore(insertChild, refChild);
+    updateNodesInserted(nodeToUpdate);
+}
+
+// If the user is inserting a list into an existing list, instead of nesting the list,
+// we put the list items into the existing list.
+Node* ReplaceSelectionCommand::insertAsListItems(PassRefPtr<Node> listElement, Node* insertionBlock, const Position& insertPos)
+{
+    while (listElement->hasChildNodes() && isListElement(listElement->firstChild()) && listElement->childNodeCount() == 1)
+        listElement = listElement->firstChild();
+
+    bool isStart = isStartOfParagraph(insertPos);
+    bool isEnd = isEndOfParagraph(insertPos);
+    bool isMiddle = !isStart && !isEnd;
+    Node* lastNode = insertionBlock;
+
+    // If we're in the middle of a list item, we should split it into two separate
+    // list items and insert these nodes between them.
+    if (isMiddle) {
+        int textNodeOffset = insertPos.offsetInContainerNode();
+        if (insertPos.node()->isTextNode() && textNodeOffset > 0)
+            splitTextNode(static_cast<Text*>(insertPos.node()), textNodeOffset);
+        splitTreeToNode(insertPos.node(), lastNode, true);
+    }
+
+    while (RefPtr<Node> listItem = listElement->firstChild()) {
+        ExceptionCode ec = 0;
+        listElement->removeChild(listItem.get(), ec);
+        ASSERT(!ec);
+        if (isStart || isMiddle)
+            insertNodeBefore(listItem, lastNode);
+        else if (isEnd) {
+            insertNodeAfter(listItem, lastNode);
+            lastNode = listItem.get();
+        } else
+            ASSERT_NOT_REACHED();
+    }
+    if (isStart || isMiddle)
+        lastNode = lastNode->previousSibling();
+    if (isMiddle)
+        insertNodeAfter(createListItemElement(document()), lastNode);
+    updateNodesInserted(lastNode);
+    return lastNode;
+}
+
+void ReplaceSelectionCommand::updateNodesInserted(Node *node)
+{
+    if (!node)
+        return;
+
+    if (!m_firstNodeInserted)
+        m_firstNodeInserted = node;
+    
+    if (node == m_lastLeafInserted)
+        return;
+    
+    m_lastLeafInserted = node->lastDescendant();
+}
+
+// During simple pastes, where we're just pasting a text node into a run of text, we insert the text node
+// directly into the text node that holds the selection.  This is much faster than the generalized code in
+// ReplaceSelectionCommand, and works around <https://bugs.webkit.org/show_bug.cgi?id=6148> since we don't 
+// split text nodes.
+bool ReplaceSelectionCommand::performTrivialReplace(const ReplacementFragment& fragment)
+{
+    if (!fragment.firstChild() || fragment.firstChild() != fragment.lastChild() || !fragment.firstChild()->isTextNode())
+        return false;
+        
+    // FIXME: Would be nice to handle smart replace in the fast path.
+    if (m_smartReplace || fragment.hasInterchangeNewlineAtStart() || fragment.hasInterchangeNewlineAtEnd())
+        return false;
+    
+    Text* textNode = static_cast<Text*>(fragment.firstChild());
+    // Our fragment creation code handles tabs, spaces, and newlines, so we don't have to worry about those here.
+    String text(textNode->data());
+    
+    Position start = endingSelection().start();
+    Position end = endingSelection().end();
+    
+    if (start.anchorNode() != end.anchorNode() || !start.anchorNode()->isTextNode())
+        return false;
+        
+    replaceTextInNode(static_cast<Text*>(start.anchorNode()), start.offsetInContainerNode(), end.offsetInContainerNode() - start.offsetInContainerNode(), text);
+    
+    end = Position(start.anchorNode(), start.offsetInContainerNode() + text.length());
+    
+    VisibleSelection selectionAfterReplace(m_selectReplacement ? start : end, end);
+    
+    setEndingSelection(selectionAfterReplace);
+    
+    return true;
+}
+
+} // namespace WebCore