Severe overuse of typedefs makes baby Torvalds sad. :-)

AnimationBitmapList_impl is just a typedef to a vector of AnimationBitmap
pointers. It's used precisely once in the code - in animate.hxx. This just
makes reading the code more difficult - too many layers of abstraction.

Change-Id: If84892dc90220c7dfe8c071d629268efa226f069