[Activity log] Rework extraction of URLs from argument lists

chrome/browser/extensions/activity_log/activity_action_constants.h

 // Copyright 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.
 
 // String constants used when logging data in the extension activity log.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTION_CONSTANTS_H_
 #define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTION_CONSTANTS_H_
 
 namespace activity_log_constants {
 
 // Keys that may be used in the "other" attribute of an Action.
 extern const char kActionBlockedReason[];
 extern const char kActionDomVerb[];
 extern const char kActionExtra[];
 extern const char kActionPrerender[];
 extern const char kActionWebRequest[];
 
 // A string used in place of the real URL when the URL is hidden because it is
 // in an incognito window.  Extension activity logs mentioning kIncognitoUrl
 // let the user know that an extension is manipulating incognito tabs without
 // recording specific data about the pages.
 extern const char kIncognitoUrl[];
 
+// A string used as a placeholder for URLs which have been removed from the
+// argument list and stored to the arg_url field.
+extern const char kArgUrlPlaceholder[];
+
 }  // namespace activity_log_constants
 
 #endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_ACTION_CONSTANTS_H_