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

chrome/browser/extensions/extension_user_script_loader.h

+// Copyright 2015 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_USER_SCRIPT_LOADER_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_USER_SCRIPT_LOADER_H_
+
+#include "base/memory/shared_memory.h"
+#include "chrome/browser/extensions/user_script_loader.h"
+#include "content/public/browser/notification_observer.h"

[Devlin, 2015/01/20 17:51:05]

nit: prune includes.

[Xi Han, 2015/01/21 21:30:16]

Done.

+#include "extensions/browser/extension_registry_observer.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/extension_set.h"
+
+namespace content {
+class BrowserContext;
+}
+
+class Profile;
+
+namespace extensions {
+
+class ContentVerifier;
+class ExtensionRegistry;
+
+// UserScriptLoader for extensions.
+class ExtensionUserScriptLoader : public UserScriptLoader,
+                                  public ExtensionRegistryObserver {
+ public:
+  // The listen_for_extension_system_loaded is only set true when initilizing
+  // the Exttension System, e.g, when constructs SharedUserScriptMaster in
+  // ExtensionSystemImpl.
+  ExtensionUserScriptLoader(Profile* profile,
+                            const ConsumerID& consumer_id,
+                            bool listen_for_extension_system_loaded);
+  ~ExtensionUserScriptLoader() override;
+
+ private:
+  static bool LoadScriptContent(const ConsumerID& consumer_id,

[Devlin, 2015/01/20 17:51:05]

nit: function comments.

[Xi Han, 2015/01/21 21:30:16]

Done.

+                                UserScript::File* script_file,
+                                const SubstitutionMap* localization_messages,
+                                scoped_refptr<ContentVerifier> verifier);
+
+  // UserScriptLoader:
+  void UpdateConsumersInfo(const ConsumerIDSet& changed_consumers) override;
+  LoadUserScriptsFunctionCallback GetLoadUserScriptsFunction() override;
+  void SendUpdate(content::RenderProcessHost* process,
+                  base::SharedMemoryHandle handle_for_process,
+                  const std::set<ConsumerID>& changed_consumers) override;
+
+  // ExtensionRegistryObserver:
+  void OnExtensionUnloaded(content::BrowserContext* browser_context,
+                           const Extension* extension,
+                           UnloadedExtensionInfo::Reason reason) override;
+
+  // Initiates script load when we have been waiting for the extension system
+  // to be ready.
+  void OnExtensionSystemReady();
+
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
+
+  base::WeakPtrFactory<ExtensionUserScriptLoader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionUserScriptLoader);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_USER_SCRIPT_LOADER_H_