Revert of [Sync] Add size and crc32c to AttachmentId.

sync/api/sync_data_unittest.cc

Index: sync/api/sync_data_unittest.cc
diff --git a/sync/api/sync_data_unittest.cc b/sync/api/sync_data_unittest.cc
index 9d45149a15959eadbdc2e9dd881dff213c748d42..94c3f4c231f05208c13b153a02a23b572972c5a5 100644
--- a/sync/api/sync_data_unittest.cc
+++ b/sync/api/sync_data_unittest.cc
@@ -72,9 +72,9 @@
 TEST_F(SyncDataTest, CreateLocalDataWithAttachments) {
   specifics.mutable_preference();
   AttachmentIdList attachment_ids;
-  attachment_ids.push_back(AttachmentId::Create(0, 0));
-  attachment_ids.push_back(AttachmentId::Create(0, 0));
-  attachment_ids.push_back(AttachmentId::Create(0, 0));
+  attachment_ids.push_back(AttachmentId::Create());
+  attachment_ids.push_back(AttachmentId::Create());
+  attachment_ids.push_back(AttachmentId::Create());
 
   SyncData data = SyncData::CreateLocalDataWithAttachments(
       kSyncTag, kNonUniqueTitle, specifics, attachment_ids);