Switching users causes wallpapers to get recreated 3 times. Other operations
like startup and rotation cause similar redundant load/draw operations. This change
tracks the various attributes that tell us when we really need to reload
and redraw, causing only one of these expensive operation per one of these
switches.
Issue #7334664 Wallpaper draws several times when switching users
Change-Id: Ic3072ef3a7eaf622d8632e87e34f50999f716c39
2f20081f9f