Tweak the layout of top app bar

- Update the color of content scrim
- Dynamically change the height of collapsing toolbar according to the
  line count of title
- Fix the jank problem of collapsing toolbar

Fixes: 184615642
Fixes: 185003521
Fixes: 182770567
Fixes: 184209747
Test: visual verified
Change-Id: I78c517eb9bec0b85997085970007481d1a4ef7d3