Add camera extension fallback toggle

Android camera extensions
(https://source.android.com/docs/core/camera/camerax-vendor-extensions)
will be able to use SW fallback implementations
on devices that do not ship the corresponding
the device specific functionality.
Since the SW fallback will be using a new data
path, it was suggested that users must be able to
control and enable/disable the SW fallback
via the Settings app.

Bug: 297083874
Test: atest packages/apps/Settings/tests/unit/src/com/android/settings/privacy/CameraExtensionsFallbackPreferenceControllerTest.java

Change-Id: I1b97777babe1c9f4ea4f2f6ee3d8251fea11146e

src/com/android/settings/privacy/CameraExtensionsFallbackPreferenceController.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2023 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.privacy;
+
+import static android.provider.Settings.Secure.CAMERA_EXTENSIONS_FALLBACK;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import com.android.settings.R;
+import com.android.settings.core.TogglePreferenceController;
+
+/**
+ * Toggle for camera extensions software fallback
+ */
+public class CameraExtensionsFallbackPreferenceController extends TogglePreferenceController {
+    public CameraExtensionsFallbackPreferenceController(Context context, String key) {
+        super(context, key);
+    }
+
+    @Override
+    public boolean isChecked() {
+        int val = Settings.Secure.getInt(mContext.getContentResolver(),
+                CAMERA_EXTENSIONS_FALLBACK, 1);
+        return val == 1;
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        int val = isChecked ? 1 : 0;
+        return Settings.Secure.putInt(mContext.getContentResolver(),
+                CAMERA_EXTENSIONS_FALLBACK, val);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public boolean isSliceable() {
+        return false;
+    }
+
+    @Override
+    public int getSliceHighlightMenuRes() {
+        // not needed since it's not sliceable
+        return NO_RES;
+    }
+}