[Android O] Initialize channels on first launch/upgrade

chrome/android/java/src/org/chromium/chrome/browser/upgrade/PackageReplacedBroadcastReceiver.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.upgrade;
 
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.os.AsyncTask;
 import android.os.Build;
 
+import org.chromium.chrome.browser.notifications.ChannelsUpdater;
+
 /**
  * Triggered when Chrome's package is replaced (e.g. when it is upgraded).
  *
  * Before changing this class, you must understand both the Receiver and Process Lifecycles:
  * http://developer.android.com/reference/android/content/BroadcastReceiver.html#ReceiverLifecycle
  *
  * - This process runs in the foreground as long as {@link #onReceive} is running.  If there are no
  *   other application components running, Android will aggressively kill it.
  *
  * - Because this runs in the foreground, don't add any code that could cause jank or ANRs.
  *
  * - This class immediately cullable by Android as soon as {@link #onReceive} returns. To kick off
  *   longer tasks, you must start a Service.
  */
 public final class PackageReplacedBroadcastReceiver extends BroadcastReceiver {
     @Override
-    public void onReceive(Context context, Intent intent) {
+    public void onReceive(final Context context, Intent intent) {
         if (!Intent.ACTION_MY_PACKAGE_REPLACED.equals(intent.getAction())) return;
+        updateChannelsIfNecessary();
         if (Build.VERSION.SDK_INT > Build.VERSION_CODES.N) return;
         UpgradeIntentService.startMigrationIfNecessary(context);
     }
+
+    private void updateChannelsIfNecessary() {
+        if (!ChannelsUpdater.getInstance().shouldUpdateChannels()) return;
+
+        final PendingResult result = goAsync();
+        new AsyncTask<Void, Void, Void>() {
+            @Override
+            protected Void doInBackground(Void... params) {
+                ChannelsUpdater.getInstance().updateChannels();
+                result.finish();
+                return null;
+            }
+        }
+                .executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
+    }
 }