Content settings clean-up: Clarify resource identifier & get rid of NO_RESOURCE_IDENTIFIER.

components/content_settings/core/common/content_settings.h

 // Copyright (c) 2011 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.
 
 #ifndef COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 44 matching lines @@
 
 struct RendererContentSettingRules {
   RendererContentSettingRules();
   ~RendererContentSettingRules();
   ContentSettingsForOneType image_rules;
   ContentSettingsForOneType script_rules;
 };
 
 namespace content_settings {
 
+typedef std::string ResourceIdentifier;
+
 // Enum containing the various source for content settings. Settings can be
 // set by policy, extension, the user or by the custodian of a supervised user.
 // Certain (internal) schemes are whilelisted. For whilelisted schemes the
 // source is |SETTING_SOURCE_WHITELIST|.
 enum SettingSource {
   SETTING_SOURCE_NONE,
   SETTING_SOURCE_POLICY,
   SETTING_SOURCE_EXTENSION,
   SETTING_SOURCE_USER,
   SETTING_SOURCE_WHITELIST,
   SETTING_SOURCE_SUPERVISED,
 };
 
 // |SettingInfo| provides meta data for content setting values. |source|
 // contains the source of a value. |primary_pattern| and |secondary_pattern|
 // contains the patterns of the appling rule.
 struct SettingInfo {
   SettingSource source;
   ContentSettingsPattern primary_pattern;
   ContentSettingsPattern secondary_pattern;
 };
 
 }  // namespace content_settings
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_H_