API for notification listener for Companioon apps

Test: 1. Trigger the confitrmation dialog.
Ensure it looks exactly like the one from settings.
2. Call an API without associating the appa first
Ensure exception is thrown with a message mentioning the need to associate 1st
Change-Id: I0b280e9bcef7f9d21ce7c9dfeaf2703945481efd

AndroidManifest.xml

@@ -2645,6 +2645,10 @@
                 android:value="true" />
         </activity>
 
+        <!-- Confirmation dialog for enabling notification access from CompanionDeviceManager -->
+        <activity android:name=".notification.NotificationAccessConfirmationActivity"
+                  android:theme="@android:style/Theme.DeviceDefault.Light.Dialog.Alert" />
+
         <receiver android:name=".widget.SettingsAppWidgetProvider"
                 android:label="@string/gadget_title"
                 android:exported="false"

src/com/android/settings/notification/NotificationAccessConfirmationActivity.java

@@ -0,0 +1,137 @@
+/*
+ * 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.notification;
+
+import static com.android.internal.notification.NotificationAccessConfirmationActivityContract
+        .EXTRA_COMPONENT_NAME;
+import static com.android.internal.notification.NotificationAccessConfirmationActivityContract
+        .EXTRA_PACKAGE_TITLE;
+import static com.android.internal.notification.NotificationAccessConfirmationActivityContract
+        .EXTRA_USER_ID;
+
+import android.Manifest;
+import android.annotation.Nullable;
+import android.app.Activity;
+import android.content.ComponentName;
+import android.content.DialogInterface;
+import android.content.pm.PackageManager;
+import android.content.pm.ServiceInfo;
+import android.os.Bundle;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.provider.SettingsStringUtil;
+import android.util.Slog;
+import android.view.accessibility.AccessibilityEvent;
+
+import com.android.internal.app.AlertActivity;
+import com.android.internal.app.AlertController;
+import com.android.settings.R;
+import com.android.settings.core.TouchOverlayManager;
+
+/** @hide */
+public class NotificationAccessConfirmationActivity extends Activity
+        implements DialogInterface {
+
+    private static final boolean DEBUG = false;
+    private static final String LOG_TAG = "NotificationAccessConfirmationActivity";
+
+    private int mUserId;
+    private ComponentName mComponentName;
+    private TouchOverlayManager mTouchOverlayManager;
+
+    @Override
+    protected void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        mTouchOverlayManager = new TouchOverlayManager(this);
+
+        mComponentName = getIntent().getParcelableExtra(EXTRA_COMPONENT_NAME);
+        mUserId = getIntent().getIntExtra(EXTRA_USER_ID, UserHandle.USER_NULL);
+        String pkgTitle = getIntent().getStringExtra(EXTRA_PACKAGE_TITLE);
+
+        AlertController.AlertParams p = new AlertController.AlertParams(this);
+        p.mTitle = getString(
+                R.string.notification_listener_security_warning_title,
+                pkgTitle);
+        p.mMessage = getString(
+                R.string.notification_listener_security_warning_summary,
+                pkgTitle);
+        p.mPositiveButtonText = getString(R.string.allow);
+        p.mPositiveButtonListener = (a, b) -> onAllow();
+        p.mNegativeButtonText = getString(R.string.deny);
+        p.mNegativeButtonListener = (a, b) -> cancel();
+        AlertController
+                .create(this, this, getWindow())
+                .installContent(p);
+    }
+
+    private void onAllow() {
+        String requiredPermission = Manifest.permission.BIND_NOTIFICATION_LISTENER_SERVICE;
+        try {
+            ServiceInfo serviceInfo = getPackageManager().getServiceInfo(mComponentName, 0);
+            if (!requiredPermission.equals(serviceInfo.permission)) {
+                Slog.e(LOG_TAG,
+                        "Service " + mComponentName + " lacks permission " + requiredPermission);
+                return;
+            }
+        } catch (PackageManager.NameNotFoundException e) {
+            Slog.e(LOG_TAG, "Failed to get service info for " + mComponentName, e);
+            return;
+        }
+
+        final SettingsStringUtil.SettingStringHelper setting =
+                 new SettingsStringUtil.SettingStringHelper(
+                         getContentResolver(),
+                         Settings.Secure.ENABLED_NOTIFICATION_LISTENERS,
+                         mUserId);
+        setting.write(SettingsStringUtil.ComponentNameSet.add(setting.read(), mComponentName));
+
+        finish();
+    }
+
+    @Override
+    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
+        return AlertActivity.dispatchPopulateAccessibilityEvent(this, event);
+    }
+
+    @Override
+    public void cancel() {
+        finish();
+    }
+
+    @Override
+    public void dismiss() {
+        // This is called after the click, since we finish when handling the
+        // click, don't do that again here.
+        if (!isFinishing()) {
+            finish();
+        }
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        mTouchOverlayManager.setOverlayAllowed(false);
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+        mTouchOverlayManager.setOverlayAllowed(true);
+    }
+}