Enable download page action for error page

chrome/browser/android/offline_pages/offline_page_utils.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_UTILS_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_UTILS_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
@@ skipping 42 matching lines @@
       content::WebContents* web_contents);
 
   // Gets the offline header provided when loading the offline page for the
   // given web contents.
   static const OfflinePageHeader* GetOfflineHeaderFromWebContents(
       content::WebContents* web_contents);
 
   // Returns true if the offline page is shown for previewing purpose.
   static bool IsShowingOfflinePreview(content::WebContents* web_contents);
 
+  // Returns true if download button is shown in the error page.
+  static bool IsShowingDownloadButtonInErrorPage(
+      content::WebContents* web_contents);
+
   // Gets an Android Tab ID from a tab containing |web_contents|. Returns false,
   // when tab is not available. Returns true otherwise and sets |tab_id| to the
   // ID of the tab.
   static bool GetTabId(content::WebContents* web_contents, int* tab_id);
 
   // Performs a check, whether pages with specified |url| and |name_space|
   // already exist. Result is returned in a |callback|, where first parameter
   // indicates whether offline pages exist, while second is a helper value to
   // report UMA, indicating the time the latest existing page with such
   // parameters was saved.
@@ skipping 16 matching lines @@
 
   static bool EqualsIgnoringFragment(const GURL& lhs, const GURL& rhs);
 
   static void StartOfflinePageDownload(content::BrowserContext* context,
                                        const GURL& url);
 };
 
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_UTILS_H_