Handle overflow, underflow in XPath substring position, length.

third_party/WebKit/Source/core/xml/XPathFunctions.h

 /*
  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006, 2009 Apple Inc.
  *
  * 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 THE AUTHOR ``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 THE AUTHOR 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.
  */
 
 #ifndef XPathFunctions_h
 #define XPathFunctions_h
 
+#include "core/CoreExport.h"
 #include "core/xml/XPathExpressionNode.h"
 
 namespace blink {
 
 namespace XPath {
 
-class Function : public Expression {
+class CORE_EXPORT Function : public Expression {
  public:
   void setArguments(HeapVector<Member<Expression>>&);
   void setName(const String& name) { m_name = name; }
 
  protected:
   Expression* arg(int pos) { return subExpr(pos); }
   const Expression* arg(int pos) const { return subExpr(pos); }
   unsigned argCount() const { return subExprCount(); }
   String name() const { return m_name; }
 
  private:
   String m_name;
 };
 
 Function* createFunction(const String& name);
-Function* createFunction(const String& name, HeapVector<Member<Expression>>&);
+CORE_EXPORT Function* createFunction(const String& name,
+                                     HeapVector<Member<Expression>>&);
 
 }  // namespace XPath
 
 }  // namespace blink
 
 #endif  // XPathFunctions_h