[Sync] Make SESSIONS an implicit type

sync/protocol/proto_value_conversions_unittest.cc

Index: sync/protocol/proto_value_conversions_unittest.cc
diff --git a/sync/protocol/proto_value_conversions_unittest.cc b/sync/protocol/proto_value_conversions_unittest.cc
index 74ae4f27275a7b3da8ee4c6503b1a0577dff8af3..8ed5440c559e0e77d7c5eb15c8a6e21f3ee19b76 100644
--- a/sync/protocol/proto_value_conversions_unittest.cc
+++ b/sync/protocol/proto_value_conversions_unittest.cc
@@ -50,7 +50,7 @@ TEST_F(ProtoValueConversionsTest, ProtoChangeCheck) {
   // If this number changes, that means we added or removed a data
   // type.  Don't forget to add a unit test for {New
   // type}SpecificsToValue below.
-  EXPECT_EQ(23, MODEL_TYPE_COUNT);
+  EXPECT_EQ(24, MODEL_TYPE_COUNT);
 
   // We'd also like to check if we changed any field in our messages.
   // However, that's hard to do: sizeof could work, but it's
@@ -232,7 +232,8 @@ TEST_F(ProtoValueConversionsTest, EntitySpecificsToValue) {
 #undef SET_FIELD
 
   scoped_ptr<DictionaryValue> value(EntitySpecificsToValue(specifics));
-  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE,
+  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE -
+            (LAST_PROXY_TYPE - FIRST_PROXY_TYPE + 1),
             static_cast<int>(value->size()));
 }