Update the remaining include paths of base/string_piece.h to its new location.

ui/webui/jstemplate_builder.h

 // 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.
 
 // This provides some helper methods for building and rendering an
 // internal html page.  The flow is as follows:
 // - instantiate a builder given a webframe that we're going to render content
 //   into
 // - load the template html and load the jstemplate javascript into the frame
 // - given a json data object, run the jstemplate javascript which fills in
 //   template values
 
 #ifndef UI_WEBUI_JSTEMPLATE_BUILDER_H_
 #define UI_WEBUI_JSTEMPLATE_BUILDER_H_
 
 #include <string>
 
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "ui/base/ui_export.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace webui {
 
 // While an object of this class is in scope, the template builder will output
 // version 2 html. Version 2 uses load_time_data.js and i18n_template2.js, and
@@ skipping 53 matching lines @@
 UI_EXPORT void AppendI18nTemplateSourceHtml(std::string* output);
 
 // Appends the code that processes the i18n Template with the JSON. You
 // should call AppendJsTemplateSourceHtml and AppendJsonHtml before calling
 // this.
 UI_EXPORT void AppendI18nTemplateProcessHtml(std::string* output);
 
 }  // namespace webui
 
 #endif  // UI_WEBUI_JSTEMPLATE_BUILDER_H_