Folder polish - update color extraction, fix contrast issues.

- Also fixes open/close animation when items were not getting clipped
  due to folder not being measured yet.

Bug: 190210234
Bug: 190164147
Test: manual
Change-Id: I230c33d7e4e1871d8d702737c56c79ce46504b8f
Merged-In: I230c33d7e4e1871d8d702737c56c79ce46504b8f