Suppress prevent ringer gesture parent page in search.

The full page verion of prevent ringing is still searchable.

- Created a new controller for parent entry.
- On the child controller, inherit the same getAvailabilityStatus() but
  override AVILABLE_UNSEARCHABLE to AVAILABLE so it becomes searchable.

Fixes: 72748524
Test: existing robotests for PreventRingingPreferenceController

Change-Id: Id2454db110c81b59fa4a98338602b03de0812f8a

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

@@ -0,0 +1,36 @@
+/*
+ * 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.settings.gestures;
+
+import android.content.Context;
+
+import com.android.settings.core.BasePreferenceController;
+
+public class PreventRingingParentPreferenceController extends BasePreferenceController {
+
+    public PreventRingingParentPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return mContext.getResources().getBoolean(
+                com.android.internal.R.bool.config_volumeHushGestureEnabled)
+                ? AVAILABLE_UNSEARCHABLE : UNSUPPORTED_ON_DEVICE;
+    }
+
+}