Pre-draw AdaptiveIconDrawable and cache it before doFrame

The AdaptiveIconDrawable can spend much time which will impact the
time for first window drawn. But usually there is a small time
between setContentView to doFrame, we can use this gap to pre-draw
the AdaptiveIconDrawable and cache it since we already know the size
and it won't change anymore.

Bug: 173975965
Test: atest StartingSurfaceDrawerTests SplashscreenTests
Change-Id: I759de2e1b4025dd150532f3fd5c67d1b404f56a0