Revert of Move JoinString to the base namespace

chrome/test/base/extension_js_browser_test.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 "chrome/test/base/extension_js_browser_test.h"
 
 #include "base/callback.h"
 #include "base/json/json_reader.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 24 matching lines @@
   ConstValueVector args;
   args.push_back(new base::StringValue(test_fixture));
   args.push_back(new base::StringValue(test_name));
   std::vector<base::string16> scripts;
   if (!libs_loaded_) {
     BuildJavascriptLibraries(&scripts);
     libs_loaded_ = true;
   }
   scripts.push_back(BuildRunTestJSCall(is_async, "RUN_TEST_F", args));
 
-  base::string16 script_16 =
-      base::JoinString(scripts, base::ASCIIToUTF16("\n"));
+  base::string16 script_16 = JoinString(scripts, '\n');
   std::string script = base::UTF16ToUTF8(script_16);
 
   std::string result =
       extensions::browsertest_util::ExecuteScriptInBackgroundPage(
           Profile::FromBrowserContext(load_waiter_->browser_context()),
           load_waiter_->extension_id(),
           script);
 
   scoped_ptr<base::Value> value_result = base::JSONReader::Read(result);
   CHECK_EQ(base::Value::TYPE_DICTIONARY, value_result->GetType());
   base::DictionaryValue* dict_value =
       static_cast<base::DictionaryValue*>(value_result.get());
   bool test_result;
   std::string test_result_message;
   CHECK(dict_value->GetBoolean("result", &test_result));
   CHECK(dict_value->GetString("message", &test_result_message));
   if (!test_result_message.empty())
     ADD_FAILURE() << test_result_message;
   return test_result;
 }