AU: Add support for signing of update payloads after they're generated.

delta_diff_generator.h

 // Copyright (c) 2010 The Chromium OS 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__
 
 #include <string>
 #include <vector>
 #include "base/basictypes.h"
@@ skipping 214 matching lines @@
   // For each block in |operation| that is read or written, find that block
   // in |blocks| and set the reader/writer field to the vertex passed.
   // |graph| is not strictly necessary, but useful for printing out
   // error messages.
   static bool AddInstallOpToBlocksVector(
       const DeltaArchiveManifest_InstallOperation& operation,
       const Graph& graph,
       Vertex::Index vertex,
       std::vector<DeltaDiffGenerator::Block>* blocks);
 
+  // Adds to |manifest| a dummy operation that points to a signature blob
+  // located at the specified offset/length.
+  static void AddSignatureOp(uint64_t signature_blob_offset,
+                             uint64_t signature_blob_length,
+                             DeltaArchiveManifest* manifest);
+
  private:
   // This should never be constructed
   DISALLOW_IMPLICIT_CONSTRUCTORS(DeltaDiffGenerator);
 };
 
 extern const char* const kBsdiffPath;
 extern const char* const kBspatchPath;
 extern const char* const kDeltaMagic;
 
 };  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__