Add return values to SyncerCommand

chrome/browser/sync/engine/build_commit_command.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_BROWSER_SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_
 #define CHROME_BROWSER_SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/sync/engine/syncer_command.h"
 #include "chrome/browser/sync/engine/syncproto.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 
 namespace browser_sync {
 
 class BuildCommitCommand : public SyncerCommand {
  public:
   BuildCommitCommand();
   virtual ~BuildCommitCommand();
 
   // SyncerCommand implementation.
-  virtual void ExecuteImpl(sessions::SyncSession* session) OVERRIDE;
+  virtual SyncerError ExecuteImpl(sessions::SyncSession* session) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(BuildCommitCommandTest, InterpolatePosition);
 
   // Functions returning constants controlling range of values.
   static int64 GetFirstPosition();
   static int64 GetLastPosition();
   static int64 GetGap();
 
   void AddExtensionsActivityToMessage(sessions::SyncSession* session,
                                       CommitMessage* message);
   // Helper for computing position.  Find the numeric position value
   // of the closest already-synced entry.  |direction| must be one of
   // NEXT_ID or PREV_ID; this parameter controls the search direction.
   // For an open range (no predecessor or successor), the return
   // value will be kFirstPosition or kLastPosition.
   int64 FindAnchorPosition(syncable::IdField direction,
                            const syncable::Entry& entry);
   // Given two values of the type returned by FindAnchorPosition,
   // compute a third value in between the two ranges.
   int64 InterpolatePosition(int64 lo, int64 hi);
 
   DISALLOW_COPY_AND_ASSIGN(BuildCommitCommand);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_BUILD_COMMIT_COMMAND_H_