Introduce DeclarativeUserScriptManager.

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"
+
+DeclarativeUserScriptManager::DeclarativeUserScriptManager(Profile* profile)
+    : profile_(profile) {
+}
+
+DeclarativeUserScriptManager::~DeclarativeUserScriptManager() {
+}
+
+extensions::DeclarativeUserScriptMaster*
+DeclarativeUserScriptManager::GetDeclarativeUserScriptMasterByID(
+    const std::string& id) {
+  UserScriptMasterMap::iterator it = declarative_user_script_masters_.find(id);
+
+  if (it != declarative_user_script_masters_.end())
+    return (it->second).get();

[Devlin, 2014/12/12 20:02:45]

nit: don't need parens around (it->second).

[Xi Han, 2014/12/12 20:32:31]

Done.

+
+  linked_ptr<extensions::DeclarativeUserScriptMaster> master(
+      new extensions::DeclarativeUserScriptMaster(profile_, id));
+  declarative_user_script_masters_[id] = master;
+  return master.get();
+}