Make sure mFullScreenScale is non-zero before animating.

If the led flash is already on when opening up the application
the background would be all black instead of blue since the value
of mFullScreenScale is at the default value of 0.

Change-Id: Id9dd00d93728c9043ee9a897ab143560c0908f60
Merge "Make sure mFullScreenScale is non-zero before animating." into cm-11.0