Move Extension into extensions namespace

chrome/common/extensions/extension_process_policy.h

 // Copyright (c) 2011 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_COMMON_EXTENSIONS_EXTENSION_PROCESS_POLICY_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_PROCESS_POLICY_H_
 #pragma once
 
-class Extension;
 class ExtensionSet;
 class ExtensionURLInfo;
 
 namespace extensions {
 
+class Extension;
+
 // Returns the extension for the given URL.  Excludes extension objects for
 // bookmark apps, which do not use the app process model.
 const Extension* GetNonBookmarkAppExtension(const ExtensionSet& extensions,
                                             const ExtensionURLInfo& url);
 
 // Check if navigating a toplevel page from |old_url| to |new_url| would cross
 // an extension process boundary (e.g. navigating from a web URL into an
 // extension URL).
 bool CrossesExtensionProcessBoundary(
     const ExtensionSet& extensions,
     const ExtensionURLInfo& old_url,
     const ExtensionURLInfo& new_url);
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_PROCESS_POLICY_H_