Revert of Move JoinString to the base namespace

remoting/base/capabilities.cc

 // Copyright 2013 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 "remoting/base/capabilities.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/stl_util.h"
@@ skipping 18 matching lines @@
 
   std::vector<std::string> host_caps = base::SplitString(
         host_capabilities, " ", base::KEEP_WHITESPACE,
         base::SPLIT_WANT_NONEMPTY);
   std::sort(host_caps.begin(), host_caps.end());
 
   std::vector<std::string> result =
       base::STLSetIntersection<std::vector<std::string> >(
           client_caps, host_caps);
 
-  return base::JoinString(result, " ");
+  return JoinString(result, " ");
 }
 
 }  // namespace remoting