Remove unneeded includes of base/string_piece.h

chrome/common/jstemplate_builder.h

 // Copyright (c) 2006-2008 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 CHROME_RENDERER_JSTEMPLATE_BUILDER_H__
-#define CHROME_RENDERER_JSTEMPLATE_BUILDER_H__
+#ifndef CHROME_COMMON_JSTEMPLATE_BUILDER_H_
+#define CHROME_COMMON_JSTEMPLATE_BUILDER_H_
 
 #include <string>
 
 #include "base/values.h"
-#include "base/string_piece.h"
+
+class StringPiece;
 
 namespace jstemplate_builder {
   // A helper function that generates a string of HTML to be loaded.  The
   // string includes the HTML and the javascript code necessary to generate the
   // full page.
   std::string GetTemplateHtml(const StringPiece& html_template,
                               const DictionaryValue* json,
                               const StringPiece& template_id);
 }  // namespace jstemplate_builder
-#endif // CHROME_RENDERER_JSTEMPLATE_BUILDER_H__
+#endif  // CHROME_COMMON_JSTEMPLATE_BUILDER_H_