[Sync] Refactor sync datatype error handling.

chrome/browser/sync/syncable/model_type_unittest.cc

Index: chrome/browser/sync/syncable/model_type_unittest.cc
diff --git a/chrome/browser/sync/syncable/model_type_unittest.cc b/chrome/browser/sync/syncable/model_type_unittest.cc
index f946f95fdba2e23075aa0dc92744d9fbd78c4c91..e532a62306cf120b1eb5fa7cf77ef1266884a652 100644
--- a/chrome/browser/sync/syncable/model_type_unittest.cc
+++ b/chrome/browser/sync/syncable/model_type_unittest.cc
@@ -78,5 +78,14 @@ TEST_F(ModelTypeTest, ModelTypeBitSetFromString) {
   EXPECT_FALSE(ModelTypeBitSetFromString(input_string, &output));
 }
 
+TEST_F(ModelTypeTest, IsDataTypeValid) {
+  EXPECT_FALSE(IsDataTypeValid(UNSPECIFIED));
+  EXPECT_FALSE(IsDataTypeValid(MODEL_TYPE_COUNT));
+  EXPECT_FALSE(IsDataTypeValid(TOP_LEVEL_FOLDER));
+  EXPECT_TRUE(IsDataTypeValid(FIRST_REAL_MODEL_TYPE));
+  EXPECT_TRUE(IsDataTypeValid(BOOKMARKS));
+  EXPECT_TRUE(IsDataTypeValid(APPS));
+}
+
 }  // namespace
 }  // namespace syncable