Adding home animation support for non-system Launcher

When user swipes up to home, Launcher will receive a onNewIntent
callwith a bundle-extra gesture_nav_contract_v1. It will contain
the componentName & UserHandle of the closing app & a callback.
Launcher can use the callback to return the final position where
the app should animate to and an optional surface to be used for
crossFade animation. The surface cleanup can be handled in
onEnterAnimationComplete.

Change-Id: I76fdd810fdcb80b71f7d7588ccac8976d9dfe278

quickstep/src/com/android/launcher3/BaseQuickstepLauncher.java

@@ -110,6 +110,13 @@ public abstract class BaseQuickstepLauncher extends Launcher
                 .getHighResLoadingState().setVisible(true);
     }
 
+    @Override
+    protected void handleGestureContract(Intent intent) {
+        if (FeatureFlags.SEPARATE_RECENTS_ACTIVITY.get()) {
+            super.handleGestureContract(intent);
+        }
+    }
+
     @Override
     public void onTrimMemory(int level) {
         super.onTrimMemory(level);