Do not typedef ExtensionId/ID, since it's already available in extension_id.h

extensions/browser/api/declarative/rules_registry.h

 // 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.
 
 #ifndef EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_H__
 #define EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_H__
 
 #include <stddef.h>
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/common/api/events.h"
+#include "extensions/common/extension_id.h"
 #include "extensions/common/one_shot_event.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace base {
 class Value;
 }  // namespace base
 
@@ skipping 114 matching lines @@
   virtual std::string RemoveRulesImpl(
       const std::string& extension_id,
       const std::vector<std::string>& rule_identifiers) = 0;
   virtual std::string RemoveAllRulesImpl(
       const std::string& extension_id) = 0;
 
  private:
   friend class base::RefCountedThreadSafe<RulesRegistry>;
   friend class RulesCacheDelegate;
 
-  typedef std::string ExtensionId;
   typedef std::string RuleId;
   typedef std::pair<ExtensionId, RuleId> RulesDictionaryKey;
   typedef std::map<RulesDictionaryKey, linked_ptr<api::events::Rule>>
       RulesDictionary;
   enum ProcessChangedRulesState {
     // ProcessChangedRules can never be called, |cache_delegate_| is NULL.
     NEVER_PROCESS,
     // A task to call ProcessChangedRules is scheduled for future execution.
     SCHEDULED_FOR_PROCESSING,
     // No task to call ProcessChangedRules is scheduled yet, but it is possible
@@ skipping 125 matching lines @@
   base::WeakPtr<RulesCacheDelegate> cache_delegate_;
 
   base::WeakPtrFactory<RulesRegistry> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RulesRegistry);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_H__