[Android] Add an about flag for Download Manager UI

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java
new file mode 100644
index 0000000000000000000000000000000000000000..09f820d02c26b47b4e969a1f98116ff591474242
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java
@@ -0,0 +1,29 @@
+// 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;
+
+import android.app.Activity;
+
+import org.chromium.chrome.browser.UrlConstants;
+import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.content_public.browser.LoadUrlParams;
+import org.chromium.ui.base.DeviceFormFactor;
+
+/**
+ * A class containing some utility static methods.
+ */
+public class DownloadUtils {
+
+    /**
+     * Displays the download manager UI. Note the UI is different on tablets and on phones.
+     */
+    public static void showDownloadManager(Activity activity, Tab tab) {
+        if (DeviceFormFactor.isTablet(activity)) {
+            tab.loadUrl(new LoadUrlParams(UrlConstants.DOWNLOADS_URL));
+        } else {
+            DownloadActivity.launch(activity);
+        }
+    }
+}