Genericize MotionRuntime.interactions() API.

Authored by markwei on Apr 24 2017, 4:16 PM.

Description

Genericize MotionRuntime.interactions() API.

Summary:
Allow not only View targets, but arbitrary targets, but with the restriction that the
type of Interactions must match the target type.

Related to https://github.com/material-motion/material-motion-android/issues/74

Reviewers: O2 Material Motion, O6 Material Android platform reviewers, Material Motion, featherless, randcode-generator

Reviewed By: O2 Material Motion, Material Motion, featherless, randcode-generator

Tags: Material Motion

Differential Revision: http://codereview.cc/D3096