Show overview as grid in fallback recents

- Replace mShowAsGrid with state specific mOverviewGridEnabled and mCurrentGestureEndTarget
- Avoid showing invisible home task in grid
- Fix quick switch out of orientation in fallback recents
- Add a HOME state to switch to when starting home, to avoid showing grid overview briefly in quick switch
- Separate clear all button and overview actions handling
- Always maintain first task's fullscreen translation at 0 to avoid jumping when mOverviewFullscreenEnabled changes
- Moved fullscreenTranslation calculation to RecentsView
- Added GestureEndTarget -> BaseState translation to allow querying displayOverviewAsGrid for a displayOverviewTasksAsGrid

Bug: 174464863
Test: Launch overveiw from home, launch overveiw from app, launch into app, test for both small and large screens
Change-Id: Iee06d94d3067ea45cadd2051717223ddc0e6e70c

quickstep/src/com/android/quickstep/FallbackActivityInterface.java

@@ -18,6 +18,7 @@ package com.android.quickstep;
 import static com.android.quickstep.SysUINavigationMode.Mode.NO_BUTTON;
 import static com.android.quickstep.fallback.RecentsState.BACKGROUND_APP;
 import static com.android.quickstep.fallback.RecentsState.DEFAULT;
+import static com.android.quickstep.fallback.RecentsState.HOME;
 
 import android.content.Context;
 import android.graphics.Rect;
@@ -81,6 +82,7 @@ public final class FallbackActivityInterface extends
     @Override
     public AnimationFactory prepareRecentsUI(RecentsAnimationDeviceState deviceState,
             boolean activityVisible, Consumer<AnimatorControllerWithResistance> callback) {
+        notifyRecentsOfOrientation(deviceState.getRotationTouchHelper());
         DefaultAnimationFactory factory = new DefaultAnimationFactory(callback);
         factory.initUI();
         return factory;
@@ -154,4 +156,25 @@ public final class FallbackActivityInterface extends
         }
         activity.<RecentsView>getOverviewPanel().startHome();
     }
+
+    @Override
+    public RecentsState stateFromGestureEndTarget(GestureState.GestureEndTarget endTarget) {
+        switch (endTarget) {
+            case RECENTS:
+                return DEFAULT;
+            case NEW_TASK:
+            case LAST_TASK:
+                return BACKGROUND_APP;
+            case HOME:
+            default:
+                return HOME;
+        }
+    }
+
+    private void notifyRecentsOfOrientation(RotationTouchHelper rotationTouchHelper) {
+        // reset layout on swipe to home
+        RecentsView recentsView = getCreatedActivity().getOverviewPanel();
+        recentsView.setLayoutRotation(rotationTouchHelper.getCurrentActiveRotation(),
+                rotationTouchHelper.getDisplayRotation());
+    }
 }