Revert of Move JoinString to the base namespace

ui/gfx/font_list_impl.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 "ui/gfx/font_list_impl.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/font_list.h"
 
 namespace {
 
 // Returns a font description from |families|, |style|, and |size_pixels|.
 std::string BuildDescription(const std::vector<std::string>& families,
                              int style,
                              int size_pixels) {
-  std::string description = base::JoinString(families, ",");
+  std::string description = JoinString(families, ',');
   description += ",";
 
   if (style & gfx::Font::BOLD)
     description += "Bold ";
   if (style & gfx::Font::ITALIC)
     description += "Italic ";
 
   description += base::IntToString(size_pixels);
   description += "px";
 
@@ skipping 157 matching lines @@
     font_style_ = fonts_[0].GetStyle();
     font_size_ = fonts_[0].GetFontSize();
   } else {
     std::vector<std::string> font_names;
     CHECK(FontList::ParseDescription(font_description_string_, &font_names,
                                      &font_style_, &font_size_));
   }
 }
 
 }  // namespace gfx