[Sync] Make SESSIONS an implicit type

chrome/browser/sync/profile_sync_service_session_unittest.cc

 // Copyright (c) 2012 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.
 
 #include <map>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ skipping 398 matching lines @@
   ASSERT_TRUE(create_root.success());
 
   // Check that the DataTypeController associated the models.
   bool has_nodes;
   ASSERT_TRUE(model_associator_->SyncModelHasUserCreatedNodes(&has_nodes));
   ASSERT_TRUE(has_nodes);
 
   // Fill an instance of session specifics with a foreign session's data.
   std::string tag = "tag1";
   sync_pb::SessionSpecifics meta;
+  DCHECK(!meta.header().has_client_name());
   BuildSessionSpecifics(tag, &meta);
   SessionID::id_type tab_nums1[] = {5, 10, 13, 17};
   std::vector<SessionID::id_type> tab_list1(
       tab_nums1, tab_nums1 + arraysize(tab_nums1));
   AddWindowSpecifics(0, tab_list1, &meta);
   std::vector<sync_pb::SessionSpecifics> tabs1;
   tabs1.resize(tab_list1.size());
   for (size_t i = 0; i < tab_list1.size(); ++i) {
     BuildTabSpecifics(tag, 0, tab_list1[i], &tabs1[i]);
   }
@@ skipping 784 matching lines @@
     sync_pb::SessionSpecifics specifics;
     header.SetSessionSpecifics(specifics);
   }
   // Ensure we associate properly despite the pre-existing node with our local
   // tag.
   error = model_associator_->AssociateModels(NULL, NULL);
   ASSERT_FALSE(error.IsSet());
 }
 
 }  // namespace browser_sync