After 90b3b9f0 we have a case where a
GifDrawable may load a frame synchronously when it’s started. If the
GifDrawable was started before it was attached to a View (and gets a 
non-null Callback) and the GifDrawable had a frame pending, then the
GifDrawable would stop itself in the start() call, causing the 
drawable not to animate. We can avoid this scenario by changing the 
order in which we start animated drawables and set them on views so that
we only start the drawable after its set on the View.

Fixes #2541