Showing previews UI for Offline Previews

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 26 matching lines @@
   // returned pointer is owned by the web_contents and may be deleted by user
   // navigation, so it is unsafe to store a copy of the returned pointer.
   static const OfflinePageItem* GetOfflinePageFromWebContents(
       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 whether the offline page corresponding to |web_contents| is part of

[jianli, 2016/10/25 22:14:16]

The comment is a bit hard to understand. How about:
  // Returns true if the offline page is shown for previewing purpose.

[RyanSturm, 2016/10/25 23:08:26]

Done.

+  // previews/. If there is no offline page for |web_contents|, returns false.
+  static bool IsShowingOfflinePreview(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);
 
   static void CheckExistenceOfPagesWithURL(
       content::BrowserContext* browser_context,
       const std::string name_space,
       const GURL& offline_url,
       const base::Callback<void(bool)>& callback);
 
   static void CheckExistenceOfRequestsWithURL(
       content::BrowserContext* browser_context,
       const std::string name_space,
       const GURL& offline_page_url,
       const base::Callback<void(bool)>& callback);
 
   static bool EqualsIgnoringFragment(const GURL& lhs, const GURL& rhs);
 };
 
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_UTILS_H_