[Extensions] Pull ExtensionId into its own file

chrome/browser/extensions/extension_management.h

 // Copyright 2014 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "base/values.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "extensions/browser/management_policy.h"
-#include "extensions/common/extension.h"
+#include "extensions/common/extension_id.h"
 #include "extensions/common/manifest.h"
 
 class GURL;
 class PrefService;
 
 namespace content {
 class BrowserContext;
 }  // namespace content
 
 namespace extensions {
 
 namespace internal {
 
 struct IndividualSettings;
 struct GlobalSettings;
 
 }  // namespace internal
 
 class APIPermissionSet;
+class Extension;
 class PermissionSet;
 
 // Tracks the management policies that affect extensions and provides interfaces
 // for observing and obtaining the global settings for all extensions, as well
 // as per-extension settings.
 class ExtensionManagement : public KeyedService {
  public:
   // Observer class for extension management settings changes.
   class Observer {
    public:
@@ skipping 157 matching lines @@
       content::BrowserContext* context) const override;
   void RegisterProfilePrefs(
       user_prefs::PrefRegistrySyncable* registry) override;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionManagementFactory);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_