Adapted the measuring of notification content view

We are now measuring all notifications content views
with AT_MOST but with an upperboundary. This allows us
to put custom views inside our normal views and still not
blow up the small size. Also adapted the dimens not to
clamp the templates

Bug: 24866646
Change-Id: If9053d84a9d91e6bc9964f64b170e3c3260a807d