Add settings for the assist gesture.

Availability of the gesture is gated by a new FeatureProvider.

Test: make -j RunSettingsRoboTests; manual test on
      supported/unsupported configurations.

Change-Id: I3529367a73e33370d5112b91d5144293ffa7fa22

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

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2017 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 android.content.Context;
+import android.provider.SearchIndexableResource;
+
+import com.android.internal.logging.nano.MetricsProto;
+import com.android.settings.R;
+import com.android.settings.core.PreferenceController;
+import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.overlay.FeatureFactory;
+import com.android.settings.search.BaseSearchIndexProvider;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class AssistGestureSettings extends DashboardFragment {
+
+    private static final String TAG = "AssistGesture";
+
+    @Override
+    public int getMetricsCategory() {
+        return MetricsProto.MetricsEvent.VIEW_UNKNOWN;
+    }
+
+    @Override
+    protected String getLogTag() {
+        return TAG;
+    }
+
+    @Override
+    protected int getPreferenceScreenResId() {
+        return R.xml.assist_gesture_settings;
+    }
+
+    @Override
+    protected List<PreferenceController> getPreferenceControllers(Context context) {
+        final List<PreferenceController> controllers = new ArrayList<>();
+        controllers.add(new AssistGesturePreferenceController(context, getLifecycle()));
+        return controllers;
+    }
+
+    public static final SearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
+            new BaseSearchIndexProvider() {
+                @Override
+                public List<SearchIndexableResource> getXmlResourcesToIndex(
+                        Context context, boolean enabled) {
+                    if (!FeatureFactory.getFactory(context).getDashboardFeatureProvider(context)
+                            .isEnabled()) {
+                        return null;
+                    }
+                    final SearchIndexableResource sir = new SearchIndexableResource(context);
+                    sir.xmlResId = R.xml.assist_gesture_settings;
+                    return Arrays.asList(sir);
+                }
+            };
+}
+