Add code path for the recents animation using window transitions.

Test: Enable in settings, swipe up

Change-Id: I1053f9e519c2f612bd3db0b66cd16ad9a30bfeb4
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index a91907d..c1883b1 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -1174,6 +1174,10 @@
         return mAllAppsController;
     }
 
+    public LauncherRootView getRootView() {
+        return (LauncherRootView) mLauncherView;
+    }
+
     public DragLayer getDragLayer() {
         return mDragLayer;
     }