Sync/Valgrind: Add gmock printers for SyncChange, SyncData, SyncError.

chrome/browser/sync/api/sync_error.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_API_SYNC_ERROR_H_
 #define CHROME_BROWSER_SYNC_API_SYNC_ERROR_H_
 #pragma once
 
+#include <iosfwd>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
 namespace tracked_objects {
 class Location;
 }  // namespace tracked_objects
 
 // Sync errors are used for debug purposes and handled internally and/or
@@ skipping 27 matching lines @@
              syncable::ModelType type);
 
   // Whether this is a valid error or not.
   bool IsSet() const;
 
   // These must only be called if IsSet() is true.
   const tracked_objects::Location& location() const;
   const std::string& message() const;
   syncable::ModelType type() const;
 
+  std::string ToString() const;
+
  private:
   // Print error information to log.
   void PrintLogError() const;
 
   // Make a copy of a SyncError. If other.IsSet() == false, this->IsSet() will
   // now return false.
   void Copy(const SyncError& other);
 
   // Initialize the local error data with the specified error data. After this
   // is called, IsSet() will return true.
   void Init(const tracked_objects::Location& location,
             const std::string& message,
             syncable::ModelType type);
 
   // Reset the error to it's default (unset) values.
   void Clear();
 
   // scoped_ptr is necessary because Location objects aren't assignable.
   scoped_ptr<tracked_objects::Location> location_;
   std::string message_;
   syncable::ModelType type_;
 };
 
+// gmock printer helper.
+void PrintTo(const SyncError& sync_error, std::ostream* os);
+
 #endif  // CHROME_BROWSER_SYNC_API_SYNC_ERROR_H_