Move JoinString to the base namespace

ui/gfx/font_render_params_linux.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 "ui/gfx/font_render_params.h"
 
 #include <fontconfig/fontconfig.h>
 
 #include "base/command_line.h"
 #include "base/containers/mru_cache.h"
@@ skipping 174 matching lines @@
   }
 
   return true;
 }
 
 // Serialize |query| into a string and hash it to a value suitable for use as a
 // cache key.
 uint32 HashFontRenderParamsQuery(const FontRenderParamsQuery& query) {
   return base::Hash(base::StringPrintf(
       "%d|%d|%d|%s|%f", query.pixel_size, query.point_size, query.style,
-      JoinString(query.families, ',').c_str(), query.device_scale_factor));
+      base::JoinString(query.families, ",").c_str(),
+      query.device_scale_factor));
 }
 
 }  // namespace
 
 FontRenderParams GetFontRenderParams(const FontRenderParamsQuery& query,
                                      std::string* family_out) {
   FontRenderParamsQuery actual_query(query);
   if (actual_query.device_scale_factor == 0) {
 #if defined(OS_CHROMEOS)
     actual_query.device_scale_factor = device_scale_factor_for_internal_display;
@@ skipping 73 matching lines @@
 float GetFontRenderParamsDeviceScaleFactor() {
   return device_scale_factor_for_internal_display;
 }
 
 void SetFontRenderParamsDeviceScaleFactor(float device_scale_factor) {
   device_scale_factor_for_internal_display = device_scale_factor;
 }
 #endif
 
 }  // namespace gfx