Add utf_string_conversions to base namespace.

chrome/test/perf/tab_switching_test.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
@@ skipping 32 matching lines @@
     show_window_ = true;
   }
 
   virtual void SetUp() {
     // Set the log_file_name_ path according to the selected browser_directory_.
     log_file_name_ = browser_directory_.AppendASCII("chrome_debug.log");
 
     // Set the log file path for the browser test.
     scoped_ptr<base::Environment> env(base::Environment::Create());
 #if defined(OS_WIN)
-    env->SetVar(env_vars::kLogFileName, WideToUTF8(log_file_name_.value()));
+    env->SetVar(env_vars::kLogFileName,
+                base::WideToUTF8(log_file_name_.value()));
 #else
     env->SetVar(env_vars::kLogFileName, log_file_name_.value());
 #endif
 
     // Add the necessary arguments to Chrome's launch command for these tests.
     AddLaunchArguments();
 
     // Run the rest of the UITest initialization.
     UITest::SetUp();
   }
@@ skipping 129 matching lines @@
   RunTabSwitchingUITest("t", true);
 }
 
 // Started failing with a webkit roll in r49936. See http://crbug.com/46751
 TEST_F(TabSwitchingUITest, DISABLED_TabSwitchRef) {
   UseReferenceBuild();
   RunTabSwitchingUITest("t_ref", true);
 }
 
 }  // namespace