PVS-Studio warning V501 for Chromium

static VisiblePosition updateAXLineStartForVisiblePosition(....)
{
  ...
  tempPosition = startPosition.previous();
  if (tempPosition.isNull() || tempPosition.isNull())
      break;
  ...
}

This suspicious code was found in Chromium project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions 'tempPosition.isNull ()' to the left and to the right of the '||' operator. webcore_remaining accessibilityobject.cpp 489

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/