Allow simultaneous scale and pan in magnified state.

1. Before in magnified state the user was able to only scale or
   pan. Based on user input this change allows performing pan
   or scale or both. If the user scales more than a threshold
   we are performing a scale and independently of that if the
   use pans more than a threshold we are performing a pan.

bug:7138928

Change-Id: Ic1511500ba3369091dcfd070669d3e4f0286fbe5