FBTF: Remove unneeded headers from base/ (part 3)

chrome/browser/extensions/external_extension_provider.h

 // 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_EXTENSION_PROVIDER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTERNAL_EXTENSION_PROVIDER_H_
 #pragma once
 
 #include <set>
 #include <string>
 
-#include "base/version.h"
 #include "chrome/common/extensions/extension.h"
 
 class FilePath;
+class Version;
 
 // This class is an abstract class for implementing external extensions
 // providers.
 class ExternalExtensionProvider {
  public:
   // ExternalExtensionProvider uses this interface to communicate back to the
   // caller what extensions are registered, and which |id|, |version| and |path|
   // they have. See also VisitRegisteredExtension below. Ownership of |version|
   // is not transferred to the visitor.
   class Visitor {
@@ skipping 16 matching lines @@
       Visitor* visitor, const std::set<std::string>& ids_to_ignore) const = 0;
 
   // Gets the version of extension with |id| and its |location|. |location| can
   // be NULL. The caller is responsible for cleaning up the Version object
   // returned. This function returns NULL if the extension is not found.
   virtual Version* RegisteredVersion(const std::string& id,
                                      Extension::Location* location) const = 0;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_EXTENSION_PROVIDER_H_