Persist offline page info in a navigation entry if needed

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageDownloadBridge.java

 // 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.offlinepages.downloads;
 
 import android.content.ComponentName;
 import android.support.annotation.Nullable;
 
 import org.chromium.base.ObserverList;
@@ skipping 157 matching lines @@
      * @param guid          GUID of the item to open.
      * @param componentName If specified, targets a specific Activity to open the offline page in.
      */
     @Override
     public void openItem(String guid, @Nullable ComponentName componentName) {
         OfflinePageDownloadItem item = getItem(guid);
         if (item == null) return;
 
         LoadUrlParams params = new LoadUrlParams(item.getUrl());
         Map<String, String> headers = new HashMap<String, String>();
-        headers.put("X-Chrome-offline", "reason=download id="
-                + Long.toString(nativeGetOfflineIdByGuid(mNativeOfflinePageDownloadBridge, guid)));
+        headers.put("X-Chrome-offline", "persist=1 reason=download id="
+                        + Long.toString(nativeGetOfflineIdByGuid(
+                                  mNativeOfflinePageDownloadBridge, guid)));
         params.setExtraHeaders(headers);
         AsyncTabCreationParams asyncParams = componentName == null
                 ? new AsyncTabCreationParams(params)
                 : new AsyncTabCreationParams(params, componentName);
         final TabDelegate tabDelegate = new TabDelegate(false);
         tabDelegate.createNewTab(asyncParams, TabLaunchType.FROM_CHROME_UI, Tab.INVALID_TAB_ID);
     }
 
     /**
      * Starts download of the page currently open in the specified Tab.
@@ skipping 87 matching lines @@
             long nativeOfflinePageDownloadBridge, List<OfflinePageDownloadItem> items);
     native OfflinePageDownloadItem nativeGetItemByGuid(
             long nativeOfflinePageDownloadBridge, String guid);
     native void nativeCancelDownload(long nativeOfflinePageDownloadBridge, String guid);
     native void nativePauseDownload(long nativeOfflinePageDownloadBridge, String guid);
     native void nativeResumeDownload(long nativeOfflinePageDownloadBridge, String guid);
     native void nativeDeleteItemByGuid(long nativeOfflinePageDownloadBridge, String guid);
     native long nativeGetOfflineIdByGuid(long nativeOfflinePageDownloadBridge, String guid);
     native void nativeStartDownload(long nativeOfflinePageDownloadBridge, Tab tab);
 }