Three way experiment for "Show saved copy" button.

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 4c16e2531f33e7df7ab293853575aa9a7747bf0e..4d880b8d46e72e17baf4e6825c2fe94026034c0a 100644
--- a/components/error_page/renderer/net_error_helper_core.h
+++ b/components/error_page/renderer/net_error_helper_core.h
@@ -45,7 +45,7 @@ class NetErrorHelperCore {
   enum Button {
     NO_BUTTON,
     RELOAD_BUTTON,
-    LOAD_STALE_BUTTON,
+    SHOW_SAVED_COPY_BUTTON,
     MORE_BUTTON,
   };
 
@@ -59,7 +59,7 @@ class NetErrorHelperCore {
         bool is_failed_post,
         scoped_ptr<error_page::ErrorPageParams> params,
         bool* reload_button_shown,
-        bool* load_stale_button_shown,
+        bool* show_saved_copy_button_shown,
         std::string* html) const = 0;
 
     // Loads the given HTML in the main frame for use as an error page.