Force expandToParagraphBoundary to return a valid EphemeralRange

third_party/WebKit/Source/core/editing/spellcheck/TextCheckingParagraph.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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
@@ skipping 19 matching lines @@
 #include "core/editing/VisiblePosition.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/editing/iterators/CharacterIterator.h"
 
 namespace blink {
 
 static EphemeralRange expandToParagraphBoundary(const EphemeralRange& range)
 {
     const VisiblePosition& start = createVisiblePosition(range.startPosition());
     DCHECK(start.isNotNull()) << range.startPosition();
-    const VisiblePosition& paragraphStart = startOfParagraph(start);
+    const Position& paragraphStart = startOfParagraph(start).deepEquivalent();
     DCHECK(paragraphStart.isNotNull()) << range.startPosition();
 
     const VisiblePosition& end = createVisiblePosition(range.endPosition());
     DCHECK(end.isNotNull()) << range.endPosition();
-    const VisiblePosition& paragraphEnd = endOfParagraph(end);
+    const Position& paragraphEnd = endOfParagraph(end).deepEquivalent();
     DCHECK(paragraphEnd.isNotNull()) << range.endPosition();
 
-    return EphemeralRange(paragraphStart.deepEquivalent(), paragraphEnd.deepEquivalent());
+    // TODO(xiaochengh): There are some cases (crbug.com/640112) where we get
+    // |paragraphStart > paragraphEnd|, which is the reason we cannot directly
+    // return |EphemeralRange(paragraphStart, paragraphEnd)|. This is not
+    // desired, though. We should do more investigation to ensure that why
+    // |paragraphStart <= paragraphEnd| is violated.
+    const Position& resultStart = paragraphStart.isNotNull() && paragraphStart <= range.startPosition() ? paragraphStart : range.startPosition();
+    const Position& resultEnd = paragraphEnd.isNotNull() && paragraphEnd >= range.endPosition() ? paragraphEnd : range.endPosition();
+    return EphemeralRange(resultStart, resultEnd);
 }
 
 TextCheckingParagraph::TextCheckingParagraph(const EphemeralRange& checkingRange)
     : m_checkingRange(checkingRange)
     , m_checkingStart(-1)
     , m_checkingEnd(-1)
     , m_checkingLength(-1)
 {
 }
 
@@ skipping 113 matching lines @@
 
 int TextCheckingParagraph::checkingLength() const
 {
     DCHECK(m_checkingRange.isNotNull());
     if (-1 == m_checkingLength)
         m_checkingLength = TextIterator::rangeLength(checkingRange().startPosition(), checkingRange().endPosition());
     return m_checkingLength;
 }
 
 } // namespace blink