Revert of Move JoinString to the base namespace

chromecast/base/metrics/cast_metrics_helper.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 "chromecast/base/metrics/cast_metrics_helper.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/metrics/histogram.h"
@@ skipping 60 matching lines @@
   *sdk_version = tokens[3];
   return true;
 }
 
 // static
 std::string CastMetricsHelper::EncodeAppInfoIntoMetricsName(
     const std::string& action_name,
     const std::string& app_id,
     const std::string& session_id,
     const std::string& sdk_version) {
-  std::string result(action_name);
-  result.push_back(kMetricsNameAppInfoDelimiter);
-  result.append(app_id);
-  result.push_back(kMetricsNameAppInfoDelimiter);
-  result.append(session_id);
-  result.push_back(kMetricsNameAppInfoDelimiter);
-  result.append(sdk_version);
-  return result;
+  std::vector<std::string> parts;
+  parts.push_back(action_name);
+  parts.push_back(app_id);
+  parts.push_back(session_id);
+  parts.push_back(sdk_version);
+  return JoinString(parts, kMetricsNameAppInfoDelimiter);
 }
 
 // static
 CastMetricsHelper* CastMetricsHelper::GetInstance() {
   DCHECK(g_instance);
   return g_instance;
 }
 
 CastMetricsHelper::CastMetricsHelper(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
@@ skipping 206 matching lines @@
     const base::TimeDelta& value) {
   // Follow UMA_HISTOGRAM_MEDIUM_TIMES definition.
   LogTimeHistogramEvent(name, value,
                         base::TimeDelta::FromMilliseconds(10),
                         base::TimeDelta::FromMinutes(3),
                         50);
 }
 
 }  // namespace metrics
 }  // namespace chromecast