Introduce HostID and de-couple Extensions from "script injection System" [browser side]

chrome/browser/extensions/declarative_user_script_manager.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_DECLARATIVE_USER_SCRIPT_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_DECLARATIVE_USER_SCRIPT_MANAGER_H_
 
 #include <map>
 
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
+#include "extensions/common/consumer.h"
 
 class Profile;
 
 namespace extensions {
 class DeclarativeUserScriptMaster;
 
 // Manages a set of DeclarativeUserScriptMaster objects for script injections.
 class DeclarativeUserScriptManager {
  public:
   explicit DeclarativeUserScriptManager(Profile* profile);
   ~DeclarativeUserScriptManager();
 
-  // Get the user script master for declarative scripts; if one does not exist,
-  // a new object will be created.
+  // Get the user script master for declarative scripts by the given id;
+  // if one does not exist, a new object will be created.
   DeclarativeUserScriptMaster* GetDeclarativeUserScriptMasterByID(
       const std::string& id);
 
  private:
+  // TODO(hanxi): add RulesRegistryID to the RulesRegistryKey.
+  struct RulesRegistryKey {
+    explicit RulesRegistryKey(const std::string& host_id) : host_id(host_id) {}
+    bool operator<(const RulesRegistryKey& key) const {
+      return host_id.compare(key.host_id) < 0;
+    }
+
+    std::string host_id;
+  };
+
+  using RulesRegistryKeyToIDMap = std::map<RulesRegistryKey, ConsumerID>;
   using UserScriptMasterMap =
-      std::map<std::string, linked_ptr<DeclarativeUserScriptMaster>>;
+      std::map<ConsumerID, linked_ptr<DeclarativeUserScriptMaster>>;
 
-  // A map of DeclarativeUserScriptMasters for ids; each master is lazily
-  // initialized.
+  // Get next available instance ID.
+  int GetNextID();
+
+  // Get the user script master for declarative scripts by the given ConsumerID.
+  DeclarativeUserScriptMaster* GetDeclarativeUserScriptMasterByID(
+      const ConsumerID& id);
+
+  // Given an input id, generate and return a ConsumerID.
+  ConsumerID* GenerateConsumerID(const std::string& id);

[Fady Samuel, 2015/01/07 19:19:40]

Return scoped_ptr<ConsumerID> to avoid accidentally leaking this thing.

[Xi Han, 2015/01/07 20:28:42]

Good point, but I realize this function hasn't been used anywhere. Removed.

+
+  // Create a DeclarativeUserScriptMaster object.
+  DeclarativeUserScriptMaster* CreateDeclarativeUserScriptMaster(
+      const ConsumerID& consumer_id);
+
+  // A map of ConsumerIDs for the given rules registry ids.
+  // Different types of input ids will define their own maps to store the
+  // mappings from ids to ConsumerIDs.
+  RulesRegistryKeyToIDMap rules_registry_key_to_id_map_;
+
+  // A map of DeclarativeUserScriptMasters for ConsumerIDs;
+  // each master is lazily initialized.
   UserScriptMasterMap declarative_user_script_masters_;
 
   Profile* profile_;
 
+  int current_instance_id_;
+
   DISALLOW_COPY_AND_ASSIGN(DeclarativeUserScriptManager);
 };
 
-}  // extensions
+}  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_DECLARATIVE_USER_SCRIPT_MANAGER_H_