Fix some problems reported by clang static analyzer

Source/core/editing/CompositeEditCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2007, 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 772 matching lines @@
         unsigned gapStart = prevBox ? prevBox->start() + prevBox->len() : 0;
         if (end < gapStart)
             // No more chance for any intersections
             break;
 
         unsigned gapEnd = box ? box->start() : length;
         bool indicesIntersect = start <= gapEnd && end >= gapStart;
         int gapLen = gapEnd - gapStart;
         if (indicesIntersect && gapLen > 0) {
             gapStart = max(gapStart, start);
-            gapEnd = min(gapEnd, end);
             if (str.isNull())
                 str = textNode->data().substring(start, end - start);
             // remove text in the gap
             str.remove(gapStart - start - removed, gapLen);
             removed += gapLen;
         }
 
         prevBox = box;
         if (box) {
             if (++sortedTextBoxesPosition < sortedTextBoxes.size())
@@ skipping 692 matching lines @@
     return node.release();
 }
 
 PassRefPtr<Element> createBlockPlaceholderElement(Document& document)
 {
     RefPtr<Element> breakNode = document.createElement(brTag, false);
     return breakNode.release();
 }
 
 } // namespace WebCore