Different rect shading options.

Gradient mode:
- current winscope rect shading

Wire frame mode:
- rects are still clickable, but z-ordering applies
- cannot click on rects that are fully covered by another
- selecting hierarchy element of covered rect will cause it to be highlighted even in wire frame view

Final screencast: https://screencast.googleplex.com/cast/NDg1NjIxMjgwNDg2MTk1MnwxMjc3OTIyZS1kNw

Bug: 339435186
Test: npm run test:unit:ci

Change-Id: Ia929e44385f959e85d22032ac7ffebd12ecacf94
14 files changed