Make removeChild faster with active ranges

third_party/WebKit/Source/core/dom/RangeBoundaryPoint.h

 /*
  * Copyright (C) 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 193 matching lines @@
         m_childBeforeBoundary = nullptr;
     } else {
         m_childBeforeBoundary = m_containerNode->lastChild();
         m_offsetInContainer = m_childBeforeBoundary ? invalidOffset : 0;
     }
     markValid();
 }
 
 inline void RangeBoundaryPoint::childBeforeWillBeRemoved()
 {
-    DCHECK(m_offsetInContainer);
     m_childBeforeBoundary = m_childBeforeBoundary->previousSibling();
+    if (!isOffsetValid())
+        return;
+    DCHECK_GT(m_offsetInContainer, 0);
     if (!m_childBeforeBoundary)
         m_offsetInContainer = 0;
     else if (m_offsetInContainer > 0)
         --m_offsetInContainer;
     markValid();
 }
 
 inline void RangeBoundaryPoint::invalidateOffset()
 {
     m_offsetInContainer = invalidOffset;
@@ skipping 14 matching lines @@
     } else {
         if (a.offset() != b.offset())
             return false;
     }
     return true;
 }
 
 } // namespace blink
 
 #endif