LayoutLib fixes for API 20 [DO NOT MERGE]

Fixes a bunch of issues with delegate method signatures.

Also cherrypicked commit 664d6f1fe4d6dfa742b3e98051f924dbc190f8ca
which is needed in this branch also.

Bug: 15492736
Change-Id: If99ff279b0d0cabe22942da27388ecb4b800c330
8 files changed