Provide activity details for task layout in ActivityStarter.

When a task is created as the result of an activity starter, there
are details present in the starter than can be useful for layout,
such as the source and launching activity records. This changelist
adds these details to the layout invocation.

Change-Id: I2d6d22c8390b03004d020d6d92196bb2a85fdd3d
Fixes: 68719294
Test: go/wm-smoke