sync: we can't lookup empty client tag nodes, so don't allow creating them

chrome/browser/sync/internal_api/syncapi_unittest.cc

 // 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.
 
 // Unit tests for the SyncApi. Note that a lot of the underlying
 // functionality is provided by the Syncable layer, which has its own
 // unit tests. We'll test SyncApi specific things in this harness.
 
 #include <cstddef>
 #include <map>
@@ skipping 672 matching lines @@
         new StrictMock<MockExtraChangeRecordData>());
     EXPECT_CALL(*extra, ToValue()).Times(2).WillRepeatedly(
         Invoke(&extra_value, &DictionaryValue::DeepCopy));
 
     record.extra.reset(extra.release());
     scoped_ptr<DictionaryValue> value(record.ToValue(&trans));
     CheckDeleteChangeRecordValue(record, *value);
   }
 }
 
+TEST_F(SyncApiTest, EmptyTags) {
+  WriteTransaction trans(FROM_HERE, test_user_share_.user_share());
+  ReadNode root_node(&trans);
+  root_node.InitByRootLookup();
+  WriteNode node(&trans);
+  std::string empty_tag;
+  EXPECT_FALSE(node.InitUniqueByCreation(
+      syncable::TYPED_URLS, root_node, empty_tag));
+  EXPECT_FALSE(node.InitByTagLookup(empty_tag));
+}
+
 namespace {
 
 class TestHttpPostProviderInterface : public HttpPostProviderInterface {
  public:
   virtual ~TestHttpPostProviderInterface() {}
 
   virtual void SetUserAgent(const char* user_agent) OVERRIDE {}
   virtual void SetExtraRequestHeaders(const char* headers) OVERRIDE {}
   virtual void SetURL(const char* url, int port) OVERRIDE {}
   virtual void SetPostPayload(const char* content_type,
@@ skipping 882 matching lines @@
     EXPECT_EQ(syncable::BOOKMARKS, node2.GetModelType());
     // We should de-canonicalize the title in GetTitle(), but the title in the
     // specifics should be stored in the server legal form.
     EXPECT_EQ(raw_title2, node2.GetTitle());
     EXPECT_EQ(title2, node2.GetBookmarkSpecifics().title());
     EXPECT_EQ(url2, node2.GetBookmarkSpecifics().url());
   }
 }
 
 }  // namespace browser_sync