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

components/error_page/renderer/net_error_helper_core.h

Index: components/error_page/renderer/net_error_helper_core.h
diff --git a/components/error_page/renderer/net_error_helper_core.h b/components/error_page/renderer/net_error_helper_core.h
index d5c8930d943d5c4f88809546b1510449b0df8f6f..1cc03f02bc69413d8387e499c296e26f89815bb7 100644
--- a/components/error_page/renderer/net_error_helper_core.h
+++ b/components/error_page/renderer/net_error_helper_core.h
@@ -5,13 +5,16 @@
 #ifndef COMPONENTS_ERROR_PAGE_RENDERER_NET_ERROR_HELPER_CORE_H_
 #define COMPONENTS_ERROR_PAGE_RENDERER_NET_ERROR_HELPER_CORE_H_
 
+#include <set>
 #include <string>
+#include <vector>
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "components/error_page/common/net_error_info.h"
+#include "components/error_page/common/offline_page_types.h"
 #include "url/gurl.h"
 
 namespace base {
@@ -50,7 +53,8 @@ class NetErrorHelperCore {
     EASTER_EGG,
     SHOW_CACHED_COPY_BUTTON,  // "Google cached copy" button label experiment.
     DIAGNOSE_ERROR,
-    SHOW_SAVED_PAGES_BUTTON,
+    SHOW_OFFLINE_PAGES_BUTTON,  // "Offline pages" experiment.
+    SHOW_OFFLINE_COPY_BUTTON,  // "Offline pages" experiment.
   };
 
   // The Delegate handles all interaction with the RenderView, WebFrame, and
@@ -62,12 +66,13 @@ class NetErrorHelperCore {
         const blink::WebURLError& error,
         bool is_failed_post,
         bool can_show_network_diagnostics_dialog,
-        bool has_offline_pages,
+        OfflinePageStatus offline_page_status,
         scoped_ptr<ErrorPageParams> params,
         bool* reload_button_shown,
         bool* show_saved_copy_button_shown,
         bool* show_cached_copy_button_shown,
-        bool* show_saved_pages_button_shown,
+        bool* show_offline_pages_button_shown,
+        bool* show_offline_copy_button_shown,
         std::string* html) const = 0;
 
     // Loads the given HTML in the frame for use as an error page.
@@ -84,7 +89,7 @@ class NetErrorHelperCore {
     virtual void UpdateErrorPage(const blink::WebURLError& error,
                                  bool is_failed_post,
                                  bool can_show_network_diagnostics_dialog,
-                                 bool has_offline_pages) = 0;
+                                 OfflinePageStatus offline_page_status) = 0;
 
     // Fetches an error page and calls into OnErrorPageFetched when done.  Any
     // previous fetch must either be canceled or finished before calling.  Can't
@@ -112,9 +117,14 @@ class NetErrorHelperCore {
     // Run the platform diagnostics too for the specified URL.
     virtual void DiagnoseError(const GURL& page_url) = 0;
 
-    // Shows the UI for offline pages.
+    // Shows all the offline pages that were saved in storage.
     virtual void ShowOfflinePages() = 0;
 
+    // Loads the offline copy of the page that was saved in storage.
+    // Note that this is different from the saved copy in the cache as in
+    // LoadPageFromCache.
+    virtual void LoadOfflineCopy(const GURL& page_url) = 0;
+
    protected:
     virtual ~Delegate() {}
   };
@@ -178,8 +188,9 @@ class NetErrorHelperCore {
                                      const std::string& api_key,
                                      const GURL& search_url);
 
-  // Notifies by the browser whether an offline page exists.
-  void OnSetHasOfflinePages(bool has_offline_pages);
+  // Notifies |this| that information about the presence of an offline version
+  // of the page has been received.
+  void OnSetOfflinePageInfo(const std::vector<GURL>& offline_page_urls);
 
   // Notifies |this| that the network's online status changed.
   // Handler for NetworkStateChanged notification from the browser process. If
@@ -235,6 +246,9 @@ class NetErrorHelperCore {
   void AutoReloadTimerFired();
   void PauseAutoReloadTimer();
 
+  OfflinePageStatus GetOfflinePageStatusForError(
+      const blink::WebURLError& error) const;
+
   static bool IsReloadableError(const ErrorPageInfo& info);
 
   Delegate* delegate_;
@@ -287,14 +301,14 @@ class NetErrorHelperCore {
 
   int auto_reload_count_;
 
+#if defined(OS_ANDROID)
+  std::set<GURL> offline_page_urls_;
+#endif  // defined(OS_ANDROID)
+
   // This value is set only when a navigation has been initiated from
   // the error page.  It is used to detect when such navigations result
   // in errors.
   Button navigation_from_button_;
-
-  // Whether an offline page exists. This is used to decide if "Show saved
-  // pages" will be provided in certain error page.
-  bool has_offline_pages_;
 };
 
 }  // namespace error_page