Merge "Synchronize stack position and size update for split screen" into pi-dev

config/boot-image-profile.txt

config/hiddenapi-light-greylist.txt

core/java/android/service/wallpaper/WallpaperService.java

core/java/android/view/IWindowSession.aidl

core/java/android/view/ViewRootImpl.java

core/java/android/view/WindowManager.java

services/core/java/com/android/server/am/ActivityStack.java

services/core/java/com/android/server/wm/Session.java

.../core/java/com/android/server/wm/TaskSnapshotSurface.java

services/core/java/com/android/server/wm/TaskStack.java

...core/java/com/android/server/wm/WindowManagerService.java

services/core/java/com/android/server/wm/WindowState.java

.../core/java/com/android/server/wm/WindowStateAnimator.java

...ssTest/src/test/windowmanagerstresstest/MainActivity.java