check network connectivity in onPageTranslated callback.

components/translate/core/browser/translate_manager.cc

 // Copyright 2014 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.
 
 #include "components/translate/core/browser/translate_manager.h"
 
 #include <map>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 343 matching lines @@
   // Trigger the "translating now" UI.
   translate_client_->ShowTranslateUI(
       translate::TRANSLATE_STEP_TRANSLATING, source_lang, target_lang,
       TranslateErrors::NONE, triggered_from_menu);
 
   TranslateScript* script = TranslateDownloadManager::GetInstance()->script();
   DCHECK(script != NULL);
 
   const std::string& script_data = script->data();
   if (!script_data.empty()) {
+    if (net::NetworkChangeNotifier::IsOffline()) {
+      translate_client_->ShowTranslateUI(
+          translate::TRANSLATE_STEP_TRANSLATE_ERROR, source_lang, target_lang,
+          TranslateErrors::NETWORK, false);
+      return;
+    }
+
     DoTranslatePage(script_data, source_lang, target_lang);
     return;
   }
 
   // The script is not available yet.  Queue that request and query for the
   // script.  Once it is downloaded we'll do the translate.
   TranslateScript::RequestCallback callback =
       base::Bind(&TranslateManager::OnTranslateScriptFetchComplete,
                  GetWeakPtr(), source_lang, target_lang);
 
@@ skipping 227 matching lines @@
           source_language) &&
       !ShouldOverrideDecision(
           metrics::TranslateEventProto::LANGUAGE_DISABLED_BY_AUTO_BLACKLIST)) {
     return true;
   }
 
   return false;
 }
 
 }  // namespace translate