Add support for pulling icons for OfflineItems

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

Index: components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/OfflineContentProvider.java
diff --git a/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/OfflineContentProvider.java b/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/OfflineContentProvider.java
index 7c177a7d4b014cf882a2005720ee3b434f0be93c..99bb6525909832a394fa537f6c206b6d3343f567 100644
--- a/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/OfflineContentProvider.java
+++ b/components/offline_items_collection/core/android/java/src/org/chromium/components/offline_items_collection/OfflineContentProvider.java
@@ -4,6 +4,8 @@
 
 package org.chromium.components.offline_items_collection;
 
+import android.support.annotation.Nullable;
+
 import java.util.ArrayList;
 
 /**
@@ -11,7 +13,20 @@ import java.util.ArrayList;
  * (components/offline_items_collection/core/offline_content_provider.h) class.
  */
 public interface OfflineContentProvider {
-    /** This interface is a Java counterpart to the C++ OfflineContentProvider::Observer
+    /**
+     * This interface is a Java counterpart to the C++ base::Callback meant to be used in response
+     * to {@link OfflineItemVisuals} requests.
+     */
+    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);
+    }
+
+    /**
+     * This interface is a Java counterpart to the C++ OfflineContentProvider::Observer
      * (components/offline_items_collection/core/offline_content_provider.h) class.
      */
     interface Observer {
@@ -52,6 +67,9 @@ public interface OfflineContentProvider {
     /** See OfflineContentProvider::GetAllItems(). */
     ArrayList<OfflineItem> getAllItems();
 
+    /** See OfflineContentProvider::GetVisualsForItem(...). */
+    void getVisualsForItem(ContentId id, VisualsCallback callback);
+
     /** See OfflineContentProvider::AddObserver(...). */
     void addObserver(Observer observer);