Consolidate dream overlay binding logic.

This changelist moves the binding logic to the
dream overlay service into the OverlayConnection
class within DreamService. This helps better
track the binding lifecycle.

Test: manual
Test: atest DreamOverlayTest
Bug: 205077932
Change-Id: I92959a9ecb53533d998abd711f960ef4fe0628d0
1 file changed