Clean up threading model of external extension providers

chrome/browser/extensions/external_registry_extension_provider_win.h

Index: chrome/browser/extensions/external_registry_extension_provider_win.h
diff --git a/chrome/browser/extensions/external_registry_extension_provider_win.h b/chrome/browser/extensions/external_registry_extension_provider_win.h
deleted file mode 100644
index 34899ae05f828e15837f037885437b5546fa40e4..0000000000000000000000000000000000000000
--- a/chrome/browser/extensions/external_registry_extension_provider_win.h
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright (c) 2009 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_EXTERNAL_REGISTRY_EXTENSION_PROVIDER_WIN_H_
-#define CHROME_BROWSER_EXTENSIONS_EXTERNAL_REGISTRY_EXTENSION_PROVIDER_WIN_H_
-#pragma once
-
-#include "chrome/browser/extensions/external_extension_provider.h"
-
-class Version;
-
-// A specialization of the ExternalExtensionProvider that uses the Registry to
-// look up which external extensions are registered.
-class ExternalRegistryExtensionProvider : public ExternalExtensionProvider {
- public:
-  ExternalRegistryExtensionProvider();
-  virtual ~ExternalRegistryExtensionProvider();
-
-  // ExternalExtensionProvider implementation:
-  virtual void VisitRegisteredExtension(Visitor* visitor) const;
-
-  virtual bool HasExtension(const std::string& id) const;
-
-  virtual bool GetExtensionDetails(const std::string& id,
-                                   Extension::Location* location,
-                                   scoped_ptr<Version>* version) const;
-};
-
-#endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_REGISTRY_EXTENSION_PROVIDER_WIN_H_