Replace invalidateChild/invalidateChildInParent

Fixes: 34361503
Test: CTS: android.view.cts.ViewGroupTest
      APCT: android.view.ViewInvalidateTest

Simplify and unify HW accelerated invalidate/damage codepaths, since
both simply walk up to ViewRootImpl and schedule a traversal.

Adds a new overridable method 'onDescendantInvalidated' for observing
subtree rendering updates.

Change-Id: I7ef1f914c3411317692451787b3810b23e019591