Revert "Remove back button when on home screen"

This reverts commit 663759e444.

Reason for revert: Temporary revert for NL build

Change-Id: I8614ee348e6e9290c0de0dfdf3e24663f220e356

quickstep/src/com/android/launcher3/uioverrides/UiFactory.java

@@ -16,11 +16,12 @@
 
 package com.android.launcher3.uioverrides;
 
-import static com.android.launcher3.LauncherState.NORMAL;
-
+import android.content.pm.PackageManager;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.PointF;
+import android.os.Bundle;
+import android.view.View;
 import android.view.View.AccessibilityDelegate;
 
 import com.android.launcher3.Launcher;
@@ -28,7 +29,6 @@ import com.android.launcher3.LauncherStateManager.StateHandler;
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.graphics.BitmapRenderer;
 import com.android.launcher3.util.TouchController;
-import com.android.quickstep.OverviewInteractionState;
 import com.android.quickstep.RecentsView;
 import com.android.systemui.shared.recents.view.RecentsTransition;
 
@@ -68,11 +68,6 @@ public class UiFactory {
         OptionsPopupView.show(launcher, touchPoint.x, touchPoint.y);
     }
 
-    public static void onLauncherStateOrFocusChanged(Launcher launcher) {
-        OverviewInteractionState.setBackButtonVisible(launcher, !launcher.isInState(NORMAL)
-                || !launcher.hasWindowFocus());
-    }
-
     public static Bitmap createFromRenderer(int width, int height, boolean forceSoftwareRenderer,
             BitmapRenderer renderer) {
         if (USE_HARDWARE_BITMAP && !forceSoftwareRenderer) {

quickstep/src/com/android/quickstep/OverviewInteractionState.java

@@ -1,64 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.quickstep;
-
-import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_HIDE_BACK_BUTTON;
-
-import android.content.Context;
-import android.os.RemoteException;
-import android.util.Log;
-
-import com.android.systemui.shared.recents.ISystemUiProxy;
-
-/**
- * Sets overview interaction flags, such as:
- *
- *   - FLAG_DISABLE_QUICK_SCRUB
- *   - FLAG_DISABLE_SWIPE_UP
- *   - FLAG_HIDE_BACK_BUTTON
- *   - FLAG_SHOW_OVERVIEW_BUTTON
- *
- * @see com.android.systemui.shared.system.NavigationBarCompat.InteractionType and associated flags.
- */
-public class OverviewInteractionState {
-
-    private static final String TAG = "OverviewFlags";
-
-    private static int sFlags;
-
-    public static void setBackButtonVisible(Context context, boolean visible) {
-        updateOverviewInteractionFlag(context, FLAG_HIDE_BACK_BUTTON, !visible);
-    }
-
-    private static void updateOverviewInteractionFlag(Context context, int flag, boolean enabled) {
-        if (enabled) {
-            sFlags |= flag;
-        } else {
-            sFlags &= ~flag;
-        }
-
-        ISystemUiProxy systemUiProxy = RecentsModel.getInstance(context).getSystemUiProxy();
-        if (systemUiProxy == null) {
-            Log.w(TAG, "Unable to update overview interaction flags; not bound to service");
-            return;
-        }
-        try {
-            systemUiProxy.setInteractionState(sFlags);
-        } catch (RemoteException e) {
-            Log.w(TAG, "Unable to update overview interaction flags", e);
-        }
-    }
-}

src/com/android/launcher3/Launcher.java

@@ -855,12 +855,6 @@ public class Launcher extends BaseActivity
         }
     }
 
-    @Override
-    public void onWindowFocusChanged(boolean hasFocus) {
-        super.onWindowFocusChanged(hasFocus);
-        mStateManager.onWindowFocusChanged();
-    }
-
     public interface LauncherOverlay {
 
         /**

src/com/android/launcher3/LauncherStateManager.java

@@ -303,12 +303,6 @@ public class LauncherStateManager {
         if (state == NORMAL) {
             setRestState(null);
         }
-
-        UiFactory.onLauncherStateOrFocusChanged(mLauncher);
-    }
-
-    public void onWindowFocusChanged() {
-        UiFactory.onLauncherStateOrFocusChanged(mLauncher);
     }
 
     public LauncherState getLastState() {

src_ui_overrides/com/android/launcher3/uioverrides/UiFactory.java

@@ -16,7 +16,6 @@
 
 package com.android.launcher3.uioverrides;
 
-import static com.android.launcher3.LauncherState.NORMAL;
 import static com.android.launcher3.LauncherState.OVERVIEW;
 
 import android.graphics.Bitmap;
@@ -62,6 +61,4 @@ public class UiFactory {
     }
 
     public static void resetOverview(Launcher launcher) { }
-
-    public static void onLauncherStateOrFocusChanged(Launcher launcher) { }
 }