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

chrome/browser/extensions/consumer_id_factory.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_CONSUMER_ID_FACTORY_H_
+#define CHROME_BROWSER_EXTENSIONS_CONSUMER_ID_FACTORY_H_
+
+#include <map>
+
+#include "base/macros.h"
+#include "chrome/browser/extensions/api/declarative_content/content_action.h"
+#include "extensions/common/consumer.h"
+
+using RequestContentScriptKey = extensions::RequestContentScript::RequestKey;
+
+namespace extensions {
+class RequestContentScript;
+}
+
+// A class that receives all kinds of input keys, convert them to
+// ConsumerIDs and return back to API consumers.
+class ConsumerIDFactory {
+ public:
+  static const ConsumerID& Create(const RequestContentScriptKey& key,

[Fady Samuel, 2015/01/08 21:03:08]

If you have a factory, it should not be possible to directly construct the
object. 

[Xi Han, 2015/01/08 22:46:46]

Remove this class, and move the map to RequstContentScript.

+                                  ConsumerID::HostType,
+                                  ConsumerID::InstanceType);
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ConsumerIDFactory);
+};
+
+#endif  //  CHROME_BROWSER_EXTENSIONS_CONSUMER_ID_FACTORY_H_