[Panlingual] Adds a filter of application for per apps locale change.

- Settings -> System -> app language -> app languages
   Use this filter to only show apps allowed to change the locale.
 - Settings -> Apps -> all apps -> any one of app -> language
   Use this filter to only show the language preference of app allowed to change the locale.
Bug: 210935436
Test: atest pass.
Test: local test.
Change-Id: I2f8a0815dae68392e11882ad9e1e4945492efdba

src/com/android/settings/applications/AppLocaleUtil.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2022 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.applications;
+
+import android.app.ActivityManager;
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.util.Log;
+
+import com.android.settings.R;
+import com.android.settingslib.applications.ApplicationsState.AppEntry;
+
+/** This class provides methods that help dealing with per app locale. */
+public class AppLocaleUtil {
+    private static final String TAG = AppLocaleUtil.class.getSimpleName();
+
+    /**
+     * Decides the UI display of per app locale.
+     */
+    public static boolean canDisplayLocaleUi(Context context, AppEntry app) {
+        return !isDisallowedPackage(context, app.info.packageName)
+                && !isSignedWithPlatformKey(context, app.info.packageName)
+                && app.hasLauncherEntry;
+    }
+
+    private static boolean isDisallowedPackage(Context context, String packageName) {
+        final String[] disallowedPackages = context.getResources().getStringArray(
+                R.array.config_disallowed_app_localeChange_packages);
+        for (String disallowedPackage : disallowedPackages) {
+            if (packageName.equals(disallowedPackage)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static boolean isSignedWithPlatformKey(Context context, String packageName) {
+        PackageInfo packageInfo = null;
+        PackageManager packageManager = context.getPackageManager();
+        ActivityManager activityManager = context.getSystemService(ActivityManager.class);
+        try {
+            packageInfo = packageManager.getPackageInfoAsUser(
+                    packageName, /* flags= */ 0,
+                    activityManager.getCurrentUser());
+        } catch (PackageManager.NameNotFoundException ex) {
+            Log.e(TAG, "package not found: " + packageName);
+        }
+        if (packageInfo == null) {
+            return false;
+        }
+        return packageInfo.applicationInfo.isSignedWithPlatformKey();
+    }
+}