[Offline Pages] Minor fix for log messages in event logger.

components/offline_pages/core/offline_event_logger_unittest.cc

 // Copyright 2016 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/offline_pages/core/offline_event_logger.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace offline_pages {
 
@@ skipping 27 matching lines @@
   EventLoggerTestClient client;
   logger.SetClient(&client);
 
   logger.SetIsLogging(true);
   for (size_t i = 0; i < kMaxLogCount + 1; ++i)
     logger.RecordActivity(kMessage + std::to_string(i));
   std::vector<std::string> log;
   logger.GetLogs(&log);
 
   EXPECT_EQ(kMaxLogCount, log.size());
-  EXPECT_EQ(client.last_log_message(), log[0]);
+  EXPECT_EQ(client.last_log_message(), log[0].substr(kTimeLength));
   EXPECT_EQ(std::string(kMessage) + std::to_string(kMaxLogCount),
-            client.last_log_message().substr(kTimeLength));
+            client.last_log_message());
 }
 
 }  // namespace offline_pages