Add "Show saved copy" button in dino page when there's offline copy

chrome/browser/android/tab_android.h

 // Copyright (c) 2012 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_TAB_ANDROID_H_
 #define CHROME_BROWSER_ANDROID_TAB_ANDROID_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
@@ skipping 109 matching lines @@
 
   void HandlePopupNavigation(chrome::NavigateParams* params);
 
   bool HasPrerenderedUrl(GURL gurl);
 
   void MakeLoadURLParams(
       chrome::NavigateParams* params,
       content::NavigationController::LoadURLParams* load_url_params);
 
   bool HasOfflinePages() const;
+  bool HasOfflineCopyForCurrentPage() const;
   void ShowOfflinePages();
+  void LoadOfflineCopy(const GURL& url);
 
   // Overridden from CoreTabHelperDelegate:
   void SwapTabContents(content::WebContents* old_contents,
                        content::WebContents* new_contents,
                        bool did_start_load,
                        bool did_finish_load) override;
 
   // Overridden from InstantServiceObserver:
   void DefaultSearchProviderChanged(
       bool google_base_url_domain_changed) override;
@@ skipping 92 matching lines @@
                                     jobject jcontent_view_core);
 
   bool HasPrerenderedUrl(JNIEnv* env, jobject obj, jstring url);
 
   // Register the Tab's native methods through JNI.
   static bool RegisterTabAndroid(JNIEnv* env);
 
  private:
   prerender::PrerenderManager* GetPrerenderManager() const;
 
+  int64_t GetBookmarkIdHelper(bool only_editable) const;
+
   const offline_pages::OfflinePageItem* GetOfflinePage(const GURL& url) const;
 
   JavaObjectWeakGlobalRef weak_java_tab_;
 
   // The identifier used by session restore for this tab.
   SessionID session_tab_id_;
 
   // Identifier of the window the tab is in.
   SessionID session_window_id_;
 
   content::NotificationRegistrar notification_registrar_;
 
   scoped_refptr<cc::Layer> content_layer_;
   chrome::android::TabContentManager* tab_content_manager_;
 
   scoped_ptr<content::WebContents> web_contents_;
   scoped_ptr<chrome::android::TabWebContentsDelegateAndroid>
       web_contents_delegate_;
 
   scoped_ptr<browser_sync::SyncedTabDelegateAndroid> synced_tab_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(TabAndroid);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_TAB_ANDROID_H_