Use wallpaper picker added to WallpaperCropper apk.

The code is still here for easier upstream merges.

Change-Id: I97ec1492e8acf7ff6a5ceef00a68f47e6444bf50
Merge "Use wallpaper picker added to WallpaperCropper apk." into cm-11.0
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0