Add support for pulling icons for OfflineItems

components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/VisualsCallback.java

Index: components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/VisualsCallback.java
diff --git a/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/VisualsCallback.java b/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/VisualsCallback.java
new file mode 100644
index 0000000000000000000000000000000000000000..ec3e12954416ec27d93b69f1af09b690140bcc31
--- /dev/null
+++ b/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/VisualsCallback.java
@@ -0,0 +1,19 @@
+// 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.components.offline_items_collection;
+
+import android.support.annotation.Nullable;
+
+/**
+ * This interface is a Java counterpart to the C++ base::Callback meant to be used in response
+ * to {@link OfflineItemVisuals} requests.
+ */
+public interface VisualsCallback {
+    /**
+     * @param id      The {@link ContentId} that {@code visuals} is associated with.
+     * @param visuals The {@link OfflineItemVisuals}, if any, associated with {@code id}.
+     */
+    void onVisualsAvailable(ContentId id, @Nullable OfflineItemVisuals visuals);
+}