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

chrome/browser/extensions/declarative_user_script_manager.cc

 // 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.
 
 #include "chrome/browser/extensions/declarative_user_script_manager.h"
 
-#include "chrome/browser/extensions/declarative_user_script_master.h"
+#include "chrome/browser/extensions/extension_declarative_user_script_master.h"
 
 namespace extensions {
 
 DeclarativeUserScriptManager::DeclarativeUserScriptManager(Profile* profile)
     : profile_(profile) {
 }
 
 DeclarativeUserScriptManager::~DeclarativeUserScriptManager() {
 }
 
-DeclarativeUserScriptMaster*
+linked_ptr<DeclarativeUserScriptMaster>
 DeclarativeUserScriptManager::GetDeclarativeUserScriptMasterByID(
-    const std::string& id) {
-  UserScriptMasterMap::iterator it = declarative_user_script_masters_.find(id);
+    const ConsumerID& consumer_id) {
+  UserScriptMasterMap::iterator it =
+      declarative_user_script_masters_.find(consumer_id);
 
   if (it != declarative_user_script_masters_.end())
-    return it->second.get();
+    return it->second;
 
-  linked_ptr<DeclarativeUserScriptMaster> master(
-      new DeclarativeUserScriptMaster(profile_, id));
-  declarative_user_script_masters_[id] = master;
-  return master.get();
+  return CreateDeclarativeUserScriptMaster(consumer_id);
 }
 
-}  // extensions
+linked_ptr<DeclarativeUserScriptMaster>
+DeclarativeUserScriptManager::CreateDeclarativeUserScriptMaster(
+    const ConsumerID& consumer_id) {
+  linked_ptr<DeclarativeUserScriptMaster> master;
+  switch (consumer_id.host_type()) {
+    case ConsumerID::EXTENSIONS:
+      master.reset(
+          new ExtensionDeclarativeUserScriptMaster(profile_, consumer_id));
+      break;
+    default:
+      master.reset(new DeclarativeUserScriptMaster(profile_, consumer_id));
+  }
+  declarative_user_script_masters_[consumer_id] = master;
+  return master;
+}
+
+}  // namespace extensions