Adding two experiment flags to definie the condition to include views in

assist structure (AS).

Flag 1: Add AutofillType != NONE views into AS
Flag 2: Add all views into AS

Both flags are default OFF and will be used to evaluate the impact of AssistStructure generating. Currently, only "importantForAutofill" and "not important views that pass the heuristic" will be included.``
bug:272129221

Change-Id: I64890a56df40b394714506ce58be23f0967fbcae