IWallpaperServiceWrapper keep track of multiple engines

Bug: 242851438
Test: WallpaperManagerTest
Change-Id: I5606cec182bdc4d24eda03a05849d6a2aab39d61
(cherry picked from commit 5822fade22e1cdb7bd81f6313b53706b22d119f2)
Merged-In: I5606cec182bdc4d24eda03a05849d6a2aab39d61
3 files changed