Use intrinsic size for path animation in AnimatedVectorDrawable

Bug 16984007

Animated Vector Drawables were using the viewport dimensions for
calculating the allowable animation error. Instead of using viewport
dimensions, it is better to use the intrinsic dimensions. Using
the viewport dimensions meant that a small viewport (e.g. 1x1)
would mean that animation paths within would only have an accuracy
of 50% of the dimensions of the drawable.

Change-Id: Id0152eabb4effd1e50c644eea7a371b38baeb7c1