Last_n: do not save snapshot of custom tabs.

chrome/browser/android/offline_pages/recent_tab_helper.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 41 matching lines @@
   // Delegate that is used by RecentTabHelper to get external dependencies.
   // Default implementation lives in .cc file, while tests provide an override.
   class Delegate {
    public:
     virtual ~Delegate() {}
     virtual std::unique_ptr<OfflinePageArchiver> CreatePageArchiver(
         content::WebContents* web_contents) = 0;
     // There is no expectations that tab_id is always present.
     virtual bool GetTabId(content::WebContents* web_contents, int* tab_id) = 0;
     virtual bool IsLowEndDevice() = 0;
+    virtual bool IsCustomTab(content::WebContents* web_contents) = 0;
   };
   void SetDelegate(std::unique_ptr<RecentTabHelper::Delegate> delegate);
 
   // Creates a request to download the current page with a properly filled
   // |client_id| and valid |request_id| issued by RequestCoordinator from a
   // suspended request. This method might be called multiple times for the same
   // page at any point after its navigation commits. There are some important
   // points about how requests are handled:
   // a) While there is an ongoing request, new requests are ignored (no
   //    overlapping snapshots).
@@ skipping 81 matching lines @@
   bool tab_is_closing_ = false;
 
   base::WeakPtrFactory<RecentTabHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RecentTabHelper);
 };
 
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_