Introduce previousPositionOf() for VisiblePosition

Source/core/editing/serializers/StyledMarkupSerializer.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009, 2010, 2011 Google Inc. All rights reserved.
  * Copyright (C) 2011 Igalia S.L.
  * Copyright (C) 2011 Motorola Mobility. 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
@@ skipping 127 matching lines @@
 {
     VisiblePosition next = v.next();
     Node* upstreamNode = mostBackwardCaretPosition(next.deepEquivalent()).anchorNode();
     Node* downstreamNode = mostForwardCaretPosition(v.deepEquivalent()).anchorNode();
     // Add an interchange newline if a paragraph break is selected and a br won't already be added to the markup to represent it.
     return isEndOfParagraph(v) && isStartOfParagraph(next) && !(isHTMLBRElement(*upstreamNode) && upstreamNode == downstreamNode);
 }
 
 static bool needInterchangeNewlineAt(const VisiblePosition& v)
 {
-    // FIXME: |v.previous()| works on a DOM tree. We need to fix this to work on
-    // a composed tree.
-    return needInterchangeNewlineAfter(v.previous());
+    // TODO(yosin) |previousPositionOf(v)| works on a DOM tree. We need to fix
+    // this to work on a composed tree.
+    return needInterchangeNewlineAfter(previousPositionOf(v));
 }
 
 template<typename Strategy>
 static bool areSameRanges(Node* node, const PositionAlgorithm<Strategy>& startPosition, const PositionAlgorithm<Strategy>& endPosition)
 {
     ASSERT(node);
     const EphemeralRange range = VisibleSelection::selectionFromContentsOfNode(node).toNormalizedEphemeralRange();
     return toPositionInDOMTree(startPosition) == range.startPosition() && toPositionInDOMTree(endPosition) == range.endPosition();
 }
 
@@ skipping 11 matching lines @@
 {
     StyledMarkupAccumulator markupAccumulator(m_shouldResolveURLs, toTextOffset(m_start.parentAnchoredEquivalent()), toTextOffset(m_end.parentAnchoredEquivalent()), m_start.document(), m_shouldAnnotate, m_convertBlocksToInlines);
 
     Node* pastEnd = m_end.nodeAsRangePastLastNode();
 
     Node* firstNode = m_start.nodeAsRangeFirstNode();
     VisiblePosition visibleStart(m_start);
     VisiblePosition visibleEnd(m_end);
     if (shouldAnnotate() && needInterchangeNewlineAfter(visibleStart)) {
         markupAccumulator.appendInterchangeNewline();
-        if (visibleStart.deepEquivalent() == visibleEnd.previous().deepEquivalent())
+        if (visibleStart.deepEquivalent() == previousPositionOf(visibleEnd).deepEquivalent())
             return markupAccumulator.takeResults();
 
         firstNode = visibleStart.next().deepEquivalent().anchorNode();
 
         if (pastEnd && PositionAlgorithm<Strategy>::beforeNode(firstNode).compareTo(PositionAlgorithm<Strategy>::beforeNode(pastEnd)) >= 0) {
             // This condition hits in editing/pasteboard/copy-display-none.html.
             return markupAccumulator.takeResults();
         }
     }
 
@@ skipping 282 matching lines @@
     if (element.isHTMLElement() && shouldAnnotate())
         inlineStyle->mergeStyleFromRulesForSerialization(&toHTMLElement(element));
 
     return inlineStyle;
 }
 
 template class StyledMarkupSerializer<EditingStrategy>;
 template class StyledMarkupSerializer<EditingInComposedTreeStrategy>;
 
 } // namespace blink