Factor Chrome details out of update manifest fetching.

chrome/browser/extensions/updater/extension_downloader_delegate.h

 // Copyright (c) 2012 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_UPDATER_EXTENSION_DOWNLOADER_DELEGATE_H_
 #define CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_DOWNLOADER_DELEGATE_H_
 
 #include <set>
 #include <string>
 
 #include "base/time/time.h"
-#include "chrome/browser/extensions/updater/manifest_fetch_data.h"
+#include "extensions/browser/updater/manifest_fetch_data.h"
 
 class GURL;
 
 namespace base {
 class FilePath;
 }
 
 namespace extensions {
 
 class ExtensionDownloaderDelegate {
@@ skipping 86 matching lines @@
 
   // Invoked to get the current version of extension |id|. Returns false if
   // that extension is not installed.
   virtual bool GetExtensionExistingVersion(const std::string& id,
                                            std::string* version) = 0;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_DOWNLOADER_DELEGATE_H_