Remove ComponentLoader's unnecessary string copy.

chrome/browser/extensions/component_loader.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 "chrome/browser/extensions/component_loader.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
@@ skipping 173 matching lines @@
   ComponentExtensionInfo info(manifest, root_directory);
   return info.extension_id;
 }
 
 std::string ComponentLoader::Add(int manifest_resource_id,
                                  const base::FilePath& root_directory) {
   if (!ignore_whitelist_for_testing_ &&
       !IsComponentExtensionWhitelisted(manifest_resource_id))
     return std::string();
 
-  std::string manifest_contents =
+  base::StringPiece manifest_contents =
       ResourceBundle::GetSharedInstance().GetRawDataResource(
-          manifest_resource_id).as_string();
+          manifest_resource_id);
   return Add(manifest_contents, root_directory, true);
 }
 
-std::string ComponentLoader::Add(const std::string& manifest_contents,
+std::string ComponentLoader::Add(const base::StringPiece& manifest_contents,
                                  const base::FilePath& root_directory) {
   return Add(manifest_contents, root_directory, false);
 }
 
-std::string ComponentLoader::Add(const std::string& manifest_contents,
+std::string ComponentLoader::Add(const base::StringPiece& manifest_contents,
                                  const base::FilePath& root_directory,
                                  bool skip_whitelist) {
   // The Value is kept for the lifetime of the ComponentLoader. This is
   // required in case LoadAll() is called again.
   base::DictionaryValue* manifest = ParseManifest(manifest_contents);
   if (manifest)
     return Add(manifest, root_directory, skip_whitelist);
   return std::string();
 }
 
@@ skipping 502 matching lines @@
       manifest.release(),
       root_directory,
       false);
   CHECK_EQ(extension_id, actual_extension_id);
   if (!done_cb.is_null())
     done_cb.Run();
 }
 #endif
 
 }  // namespace extensions