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chrome/android/java/src/org/chromium/chrome/browser/download/ui/LoadingStateDelegate.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/ui/LoadingStateDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/ui/LoadingStateDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/LoadingStateDelegate.java
new file mode 100644
index 0000000000000000000000000000000000000000..c791df958fd3b6d04b942bf432e92da316917a45
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/LoadingStateDelegate.java
@@ -0,0 +1,54 @@
+// Copyright 2016 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.ui;
+
+/**
+ * Determines when the data from all of the backends has been loaded.
+ * <p>
+ * TODO(ianwen): add a timeout mechanism to either the DownloadLoadingDelegate or to the
+ * backend so that if it takes forever to load one of the backend, users are still able to see
+ * the other two.
+ */
+public class LoadingStateDelegate {
+    public static final int REGULAR_DOWNLOADS = 0b001;
+    public static final int INCOGNITO_DOWNLOADS = 0b010;
+    public static final int OFFLINE_PAGES = 0b100;
+
+    private static final int ALL_LOADED = 0b111;
+
+    private int mLoadingState;
+    private int mPendingFilter = DownloadFilter.FILTER_ALL;
+
+    /** @param offTheRecord Whether this delegate needs to consider incognito. */
+    public LoadingStateDelegate(boolean offTheRecord) {
+        // If we don't care about incognito, mark it as loaded.
+        mLoadingState = offTheRecord ? 0 : INCOGNITO_DOWNLOADS;
+    }
+
+    /**
+     * Tells this delegate one of the three backends has been loaded.
+     * @param backendFlag Which backend was loaded.
+     * @return Whether or not the backends are all loaded.
+     */
+    public boolean updateLoadingState(int backendFlag) {
+        mLoadingState |= backendFlag;
+        return isLoaded();
+    }
+
+    /** @return Whether all backends are loaded. */
+    public boolean isLoaded() {
+        return mLoadingState == ALL_LOADED;
+    }
+
+    /** Caches a filter for when the backends have loaded. */
+    public void setPendingFilter(int filter) {
+        mPendingFilter = filter;
+    }
+
+    /** @return The cached filter, or {@link DownloadFilter#FILTER_ALL} if none was set. */
+    public int getPendingFilter() {
+        return mPendingFilter;
+    }
+}