Remove redundant computeScroll() call for hw-accelerated views

View.draw() calls computeScroll() to initialize scrolling values correctly.
But getDisplayList() also calls computeScroll() for the same reason, resulting
in 2 calls to that method for hw-accelerated views.
Fix: avoid calling computeScroll() in View.draw() for views with display lists.

Change-Id: I57a3862e2d554752cd0fdb862513cbb3dfb3105c