Add support for pulling icons for OfflineItems

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

 // 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.os.Handler;
+
 import org.chromium.base.ObserverList;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 
 import java.util.ArrayList;
 
 /**
  * A helper class responsible for exposing the C++ OfflineContentAggregator
  * (components/offline_items_collection/core/offline_content_aggregator.h) class to Java.  This
  * class is created and owned by it's C++ counterpart OfflineContentAggregatorBridge
  * (components/offline_items_collection/core/android/offline_content_aggregator_bridge.h).
  */
 @JNINamespace("offline_items_collection::android")
 public class OfflineContentAggregatorBridge implements OfflineContentProvider {
+    private final Handler mHandler = new Handler();
+
     private long mNativeOfflineContentAggregatorBridge;
     private ObserverList<OfflineContentProvider.Observer> mObservers;
     private boolean mItemsAvailable;
 
     /**
      * A private constructor meant to be called by the C++ OfflineContentAggregatorBridge.
      * @param nativeOfflineContentAggregatorBridge A C++ pointer to the
      * OfflineContentAggregatorBridge.
      */
     private OfflineContentAggregatorBridge(long nativeOfflineContentAggregatorBridge) {
@@ skipping 44 matching lines @@
         return nativeGetItemById(mNativeOfflineContentAggregatorBridge, id.namespace, id.id);
     }
 
     @Override
     public ArrayList<OfflineItem> getAllItems() {
         if (mNativeOfflineContentAggregatorBridge == 0) return null;
         return nativeGetAllItems(mNativeOfflineContentAggregatorBridge);
     }
 
     @Override
-    public void addObserver(OfflineContentProvider.Observer observer) {
-        mObservers.addObserver(observer);
+    public void getVisualsForItem(ContentId id, VisualsCallback callback) {
+        nativeGetVisualsForItem(
+                mNativeOfflineContentAggregatorBridge, id.namespace, id.id, callback);
     }
 
     @Override
+    public void addObserver(final OfflineContentProvider.Observer observer) {
+        mObservers.addObserver(observer);
+        if (!areItemsAvailable()) return;
+
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                notifyObserverOfItemsReady(observer);
+            }
+        });
+    }
+
+    @Override
     public void removeObserver(OfflineContentProvider.Observer observer) {
         mObservers.removeObserver(observer);
     }
 
+    private void notifyObserverOfItemsReady(Observer observer) {
+        if (!mObservers.hasObserver(observer)) return;
+        observer.onItemsAvailable();
+    }
+
     // Methods called from C++ via JNI.
     @CalledByNative
     private void onItemsAvailable() {
         mItemsAvailable = true;
 
         for (Observer observer : mObservers) {
             observer.onItemsAvailable();
         }
     }
 
@@ skipping 15 matching lines @@
         }
     }
 
     @CalledByNative
     private void onItemUpdated(OfflineItem item) {
         for (Observer observer : mObservers) {
             observer.onItemUpdated(item);
         }
     }
 
+    @CalledByNative
+    private static void onVisualsAvailable(
+            VisualsCallback callback, String nameSpace, String id, OfflineItemVisuals visuals) {
+        callback.onVisualsAvailable(new ContentId(nameSpace, id), visuals);
+    }
+
     /**
      * Called when the C++ OfflineContentAggregatorBridge is destroyed.  This tears down the Java
      * component of the JNI bridge so that this class, which may live due to other references, no
      * longer attempts to access the C++ side of the bridge.
      */
     @CalledByNative
     private void onNativeDestroyed() {
         mNativeOfflineContentAggregatorBridge = 0;
     }
 
@@ skipping 17 matching lines @@
     private native void nativeCancelDownload(
             long nativeOfflineContentAggregatorBridge, String nameSpace, String id);
     private native void nativePauseDownload(
             long nativeOfflineContentAggregatorBridge, String nameSpace, String id);
     private native void nativeResumeDownload(
             long nativeOfflineContentAggregatorBridge, String nameSpace, String id);
     private native OfflineItem nativeGetItemById(
             long nativeOfflineContentAggregatorBridge, String nameSpace, String id);
     private native ArrayList<OfflineItem> nativeGetAllItems(
             long nativeOfflineContentAggregatorBridge);
+    private native void nativeGetVisualsForItem(long nativeOfflineContentAggregatorBridge,
+            String nameSpace, String id, VisualsCallback callback);
 }