Add UMA histograms for Google cached copy experiment on network error interstitial

chrome/renderer/net/net_error_helper.cc

Index: chrome/renderer/net/net_error_helper.cc
diff --git a/chrome/renderer/net/net_error_helper.cc b/chrome/renderer/net/net_error_helper.cc
index ce995aac723c56e3485b43d38d21807b20229b57..588cf27caf1b7592ee18289476ac822707f5fb5e 100644
--- a/chrome/renderer/net/net_error_helper.cc
+++ b/chrome/renderer/net/net_error_helper.cc
@@ -167,6 +167,8 @@ void NetErrorHelper::GenerateLocalizedErrorPage(
     scoped_ptr<ErrorPageParams> params,
     bool* reload_button_shown,
     bool* show_saved_copy_button_shown,
+    bool* show_cached_copy_button_shown,
+    bool* show_cached_page_button_shown,
     std::string* error_html) const {
   error_html->clear();
 
@@ -188,6 +190,19 @@ void NetErrorHelper::GenerateLocalizedErrorPage(
     *show_saved_copy_button_shown =
         error_strings.Get("showSavedCopyButton", NULL);
 
+    bool show_cache_copy_button_default_label;
+    bool showing_cache_copy_experiment =
+        error_strings.GetBoolean("cacheButton.defaultLabel",
+        &show_cache_copy_button_default_label);
+    if (showing_cache_copy_experiment) {
+      if (show_cache_copy_button_default_label) {
+        *show_cached_copy_button_shown = false;
+        *show_cached_page_button_shown = true;
+      } else {
+        *show_cached_page_button_shown = false;
+        *show_cached_copy_button_shown = true;
+      }
+    }
     // "t" is the id of the template's root node.
     *error_html = webui::GetTemplatesHtml(template_html, &error_strings, "t");
   }