[Android O] Upstreaming notification channels code

chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java

Index: chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java
new file mode 100644
index 0000000000000000000000000000000000000000..609be47354a260390696b7334e5fbc25332087ce
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java
@@ -0,0 +1,45 @@
+// Copyright 2017 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.notifications;
+
+import android.content.Context;
+
+import org.chromium.base.BuildInfo;
+import org.chromium.base.ContextUtils;
+
+/**
+ * Factory which supplies the appropriate type of notification builder based on Android version.
+ * Should be used for all notifications we create, to ensure a notification channel is set on O.
+ */
+public class NotificationBuilderFactory {
+    /**
+     * Creates either a Notification.Builder or NotificationCompat.Builder under the hood, wrapped
+     * in our own common interface.
+     *
+     * TODO(crbug.com/704152) Remove this once we've updated to revision 26 of the support library.
+     * Then we can use NotificationCompat.Builder and set the channel directly everywhere.
+     *
+     * @param preferCompat true if a NotificationCompat.Builder is preferred.
+     *                     A Notification.Builder will be used regardless on Android O.
+     * @param channelId The ID of the channel the notification should be posted to.
+     * @param channelName The name of the channel the notification should be posted to.
+     *                    Used to create the channel if a channel with channelId does not exist.
+     * @param channelGroupId The ID of the channel group the channel belongs to. Used when creating
+     *                       the channel if a channel with channelId does not exist.
+     * @param channelGroupName The name of the channel group the channel belongs to.
+     *                         Used to create the channel group if a channel group with
+     *                         channelGroupId does not already exist.
+     */
+    public static ChromeNotificationBuilder createChromeNotificationBuilder(boolean preferCompat,
+            String channelId, String channelName, String channelGroupId, String channelGroupName) {
+        Context context = ContextUtils.getApplicationContext();
+        if (BuildInfo.isAtLeastO()) {
+            return new NotificationBuilderForO(ContextUtils.getApplicationContext(), channelId,
+                    channelName, channelGroupId, channelGroupName);
+        }
+        return preferCompat ? new NotificationCompatBuilder(context)
+                            : new NotificationBuilder(context);
+    }
+}