Performance improvements for Dash

[Apurv Jyotirmay]

Among various things with Unity desktop, one thing I noticed was that
whenever I will launch the dash, the system fans will go up and if there is
any video playing in the background of dash, then it will start to freeze.

The entire Unity desktop works fine, but it is this one thing that just
ruins the fun of using the desktop. Something different needs to be done
with the dash like introducing some cosmetic or under the hood changes for
the dash to make the user experience more fluid.