Atomic UserScript ID generation

chrome/common/extensions/manifest_handlers/content_scripts_handler.cc

 // Copyright (c) 2013 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/common/extensions/manifest_handlers/content_scripts_handler.h"
 
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 14 matching lines @@
 #include "url/gurl.h"
 
 namespace extensions {
 
 namespace keys = extensions::manifest_keys;
 namespace values = manifest_values;
 namespace errors = manifest_errors;
 
 namespace {
 
-// The globally-unique id for a user script.
-int64 g_next_user_script_id = 0;
-
 // Helper method that loads either the include_globs or exclude_globs list
 // from an entry in the content_script lists of the manifest.
 bool LoadGlobsHelper(const base::DictionaryValue* content_script,
                      int content_script_index,
                      const char* globs_property_name,
                      base::string16* error,
                      void(UserScript::*add_method)(const std::string& glob),
                      UserScript* instance) {
   if (!content_script->HasKey(globs_property_name))
     return true;  // they are optional
@@ skipping 373 matching lines @@
                                       &user_script)) {
       return false;  // Failed to parse script context definition.
     }
 
     user_script.set_extension_id(extension->id());
     if (extension->converted_from_user_script()) {
       user_script.set_emulate_greasemonkey(true);
       // Greasemonkey matches all frames.
       user_script.set_match_all_frames(true);
     }
-    user_script.set_id(g_next_user_script_id++);
+    user_script.set_id(UserScript::GenerateUserScriptID());
     content_scripts_info->content_scripts.push_back(user_script);
   }
   extension->SetManifestData(keys::kContentScripts,
                              content_scripts_info.release());
   PermissionsParser::SetScriptableHosts(
       extension, ContentScriptsInfo::GetScriptableHosts(extension));
   return true;
 }
 
 bool ContentScriptsHandler::Validate(
@@ skipping 33 matching lines @@
       if (!IsScriptValid(path, css_script.relative_path(),
                          IDS_EXTENSION_LOAD_CSS_FAILED, error))
         return false;
     }
   }
 
   return true;
 }
 
 }  // namespace extensions