Do not theme icons when the original view is not themed.

Fixes bug where animations uses themed icons in All Apps, where the
icons are not themed.

We want the DragView themed since all valid drop locations will have it
appear themed.

Bug: 215650713
Test: open/close an app from All Apps
Change-Id: I9969ce4921831dd12858ed9b0fe64379e9e3b188