Improper position of selection handlers on scroll

Improper position of selection handlers on scroll

[Title] Improper position of selection handlers on scroll
[Issue#] WEB-2943
[Problem] When a long text is selcted and then the page is
  scrolled with the selection the handlers get algned to
  start of the view port insteed of start of the selection
[Cause] Invalid point calculation of the handlers if the
  selection rect does not fall in the view port. So the
  first intersection point was considred for the calculation
  which was the start of view port
[Solution] This calculation is not required. The rect which
  is obtained is including all the text rects

Change-Id: I66a484269eee252605c1b733a5d9be5cc7d86802