Extensions: Consolidate extension id hashing / searching.

extensions/common/extension.h

 // Copyright (c) 2013 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 EXTENSIONS_COMMON_EXTENSION_H_
 #define EXTENSIONS_COMMON_EXTENSION_H_
 
 #include <algorithm>
 #include <iosfwd>
 #include <map>
@@ skipping 300 matching lines @@
   }
   PermissionsParser* permissions_parser() { return permissions_parser_.get(); }
   const PermissionsParser* permissions_parser() const {
     return permissions_parser_.get();
   }
 
   const PermissionsData* permissions_data() const {
     return permissions_data_.get();
   }
 
+  // Returns a hash for the extension id.
+  std::string HashedIdInHex() const;
+
   // Appends |new_warning[s]| to install_warnings_.
   void AddInstallWarning(const InstallWarning& new_warning);
   void AddInstallWarnings(const std::vector<InstallWarning>& new_warnings);
   const std::vector<InstallWarning>& install_warnings() const {
     return install_warnings_;
   }
   const extensions::Manifest* manifest() const {
     return manifest_.get();
   }
   bool wants_file_access() const { return wants_file_access_; }
@@ skipping 247 matching lines @@
 
   UpdatedExtensionPermissionsInfo(
       const Extension* extension,
       const PermissionSet* permissions,
       Reason reason);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EXTENSION_H_