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

chrome/browser/extensions/shared_user_script_master.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/shared_user_script_master.h"
 
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/extensions/manifest_handlers/content_scripts_handler.h"
 #include "extensions/browser/extension_registry.h"
+#include "extensions/common/host_id.h"
 
 namespace extensions {
 
 SharedUserScriptMaster::SharedUserScriptMaster(Profile* profile)
     : loader_(profile,
-              std::string() /* owner_extension_id */,
+              HostID(),
               true /* listen_for_extension_system_loaded */),
       profile_(profile),
       extension_registry_observer_(this) {
   extension_registry_observer_.Add(ExtensionRegistry::Get(profile_));
 }
 
 SharedUserScriptMaster::~SharedUserScriptMaster() {
 }
 
 void SharedUserScriptMaster::OnExtensionLoaded(
@@ skipping 20 matching lines @@
        ++it) {
     UserScript script = *it;
     script.set_incognito_enabled(incognito_enabled);
     script_set.insert(script);
   }
 
   return script_set;
 }
 
 }  // namespace extensions