Glue OfflineContentProvider to the download service

chrome/android/java/src/org/chromium/chrome/browser/download/items/OfflineContentAggregatorNotificationBridgeUiFactory.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/items/OfflineContentAggregatorNotificationBridgeUiFactory.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/items/OfflineContentAggregatorNotificationBridgeUiFactory.java b/chrome/android/java/src/org/chromium/chrome/browser/download/items/OfflineContentAggregatorNotificationBridgeUiFactory.java
new file mode 100644
index 0000000000000000000000000000000000000000..c8bf22ff32f484c60c34312e77501c5118d5c417
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/items/OfflineContentAggregatorNotificationBridgeUiFactory.java
@@ -0,0 +1,47 @@
+// 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.download.items;
+
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.browser.profiles.Profile;
+import org.chromium.components.offline_items_collection.OfflineContentProvider;
+
+/**
+ * A factory meant to hold a singleton bridge between the notification UI and an
+ * {@link OfflineContentProvider}.
+ */
+public class OfflineContentAggregatorNotificationBridgeUiFactory {
+    private static OfflineContentAggregatorNotificationBridgeUi sBridgeUi;
+
+    /**
+     * @return An {@link OfflineContentAggregatorNotificationBridgeUi} instance singleton.  If one
+     *         is not available this will create a new one.
+     */
+    public static OfflineContentAggregatorNotificationBridgeUi instance() {
+        ThreadUtils.assertOnUiThread();
+        if (sBridgeUi == null) {
+            Profile profile = Profile.getLastUsedProfile();
+            OfflineContentProvider provider = OfflineContentAggregatorFactory.forProfile(profile);
+
+            sBridgeUi = new OfflineContentAggregatorNotificationBridgeUi(provider);
+        }
+
+        return sBridgeUi;
+    }
+
+    /**
+     * Destroys the internal singleton for {@link OfflineContentAggregatorNotificationBridgeUi} if
+     * one exists.
+     */
+    public static void destroy() {
+        ThreadUtils.assertOnUiThread();
+        if (sBridgeUi == null) return;
+
+        sBridgeUi.destroy();
+        sBridgeUi = null;
+    }
+
+    private OfflineContentAggregatorNotificationBridgeUiFactory() {}
+}