Add setting to allow configuration of long press home gesture

This allows configuration of long press home gesture on 2-/3-button navigation configurations. It allows the user to enable and disable the invocation of assistant app using said gesture.

Bug: 191888710
Test: Unit tests and on a physical device.
Change-Id: I18cb290058ac5c2a748d40802b942404f548b868

src/com/android/settings/gestures/ButtonNavigationSettingsFragment.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2021 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.settings.gestures;
+
+import static android.view.WindowManagerPolicyConstants.NAV_BAR_MODE_2BUTTON_OVERLAY;
+import static android.view.WindowManagerPolicyConstants.NAV_BAR_MODE_3BUTTON_OVERLAY;
+
+import android.app.settings.SettingsEnums;
+import android.content.Context;
+
+import com.android.settings.R;
+import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.search.BaseSearchIndexProvider;
+import com.android.settingslib.search.SearchIndexable;
+
+/**
+ * A fragment that includes settings for 2- and 3-button navigation modes.
+ */
+@SearchIndexable(forTarget = SearchIndexable.MOBILE)
+public class ButtonNavigationSettingsFragment extends DashboardFragment {
+
+    private static final String TAG = "ButtonNavigationSettingsFragment";
+
+    public static final String BUTTON_NAVIGATION_SETTINGS =
+            "com.android.settings.BUTTON_NAVIGATION_SETTINGS";
+
+
+    @Override
+    public int getMetricsCategory() {
+        return SettingsEnums.SETTINGS_BUTTON_NAV_DLG;
+    }
+
+    @Override
+    protected int getPreferenceScreenResId() {
+        return R.xml.button_navigation_settings;
+    }
+
+    @Override
+    protected String getLogTag() {
+        return TAG;
+    }
+
+    public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
+            new BaseSearchIndexProvider(R.xml.button_navigation_settings) {
+
+                @Override
+                protected boolean isPageSearchEnabled(Context context) {
+                    return SystemNavigationPreferenceController.isOverlayPackageAvailable(context,
+                            NAV_BAR_MODE_2BUTTON_OVERLAY)
+                            || SystemNavigationPreferenceController.isOverlayPackageAvailable(
+                            context,
+                            NAV_BAR_MODE_3BUTTON_OVERLAY);
+                }
+            };
+}