tree a60f824a2bbe83e34068fbb55d5963b9d721384d
parent 12461a16c9afed84418d2863bdf00ea512fbeab7
author Jon Miranda <jonmiranda@google.com> 1498181685 -0700
committer Jon Miranda <jonmiranda@google.com> 1498181685 -0700

Move PreviewBackground into its own class file.

This is done in preparation for new PreviewBackground animation
where we will be animating in the first page preview items when
closing the Folder from a non-first page.

Bug: 36022592
Bug: 35064148
Change-Id: Id4d54da16ddfa852ca639a2dc8d328307d4d443a