Extensions: Consolidate extension id hashing / searching.

components/crx_file/id_util.h

 // Copyright 2014 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 COMPONENTS_CRX_FILE_ID_UTIL_H_
 #define COMPONENTS_CRX_FILE_ID_UTIL_H_
 
 #include <string>
 
 namespace base {
 class FilePath;
 }
 
 namespace crx_file {
 namespace id_util {
 
 // The number of bytes in a legal id.
 extern const size_t kIdSize;
 
 // Generates an extension ID from arbitrary input. The same input string will
 // always generate the same output ID.
 std::string GenerateId(const std::string& input);
 
-// Generate an ID for an extension in the given path.
+// Generates an ID for an extension in the given path.
 // Used while developing extensions, before they have a key.
 std::string GenerateIdForPath(const base::FilePath& path);
 
-// Normalize the path for use by the extension. On Windows, this will make
+// Returns the hash of an extension ID in hex.
+std::string HashedIdInHex(const std::string& id);
+
+// Normalizes the path for use by the extension. On Windows, this will make
 // sure the drive letter is uppercase.
 base::FilePath MaybeNormalizePath(const base::FilePath& path);
 
 // Checks if |id| is a valid extension-id. Extension-ids are used for anything
 // that comes in a CRX file, including apps, extensions, and components.
 bool IdIsValid(const std::string& id);
 
 }  // namespace id_util
 }  // namespace crx_file
 
 #endif  // COMPONENTS_CRX_FILE_ID_UTIL_H_