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

sync/syncable/directory_unittest.cc

Index: sync/syncable/directory_unittest.cc
diff --git a/sync/syncable/directory_unittest.cc b/sync/syncable/directory_unittest.cc
index 5f8cbed23c2225e3827f09a905586f6f8e4eaa5a..64f3b57f3fbc42f2a51edef6e4ac09db07c3d891 100644
--- a/sync/syncable/directory_unittest.cc
+++ b/sync/syncable/directory_unittest.cc
@@ -1639,7 +1639,7 @@
   sync_pb::AttachmentMetadata attachment_metadata;
   sync_pb::AttachmentMetadataRecord* record = attachment_metadata.add_record();
   sync_pb::AttachmentIdProto attachment_id_proto =
-      syncer::CreateAttachmentIdProto(0, 0);
+      syncer::CreateAttachmentIdProto();
   *record->mutable_id() = attachment_id_proto;
   ASSERT_FALSE(dir()->IsAttachmentLinked(attachment_id_proto));
   {
@@ -1683,8 +1683,8 @@
   sync_pb::AttachmentMetadata attachment_metadata;
   sync_pb::AttachmentMetadataRecord* r1 = attachment_metadata.add_record();
   sync_pb::AttachmentMetadataRecord* r2 = attachment_metadata.add_record();
-  *r1->mutable_id() = syncer::CreateAttachmentIdProto(0, 0);
-  *r2->mutable_id() = syncer::CreateAttachmentIdProto(0, 0);
+  *r1->mutable_id() = syncer::CreateAttachmentIdProto();
+  *r2->mutable_id() = syncer::CreateAttachmentIdProto();
   sync_pb::AttachmentIdProto attachment_id_proto = r1->id();
 
   WriteTransaction trans(FROM_HERE, UNITTEST, dir().get());
@@ -1713,7 +1713,7 @@
   sync_pb::AttachmentMetadata attachment_metadata;
   sync_pb::AttachmentMetadataRecord* record = attachment_metadata.add_record();
   sync_pb::AttachmentIdProto attachment_id_proto =
-      syncer::CreateAttachmentIdProto(0, 0);
+      syncer::CreateAttachmentIdProto();
   *record->mutable_id() = attachment_id_proto;
   ASSERT_FALSE(dir()->IsAttachmentLinked(attachment_id_proto));
   const Id id = TestIdFactory::FromNumber(-1);
@@ -1742,7 +1742,7 @@
   sync_pb::AttachmentMetadata attachment_metadata;
   sync_pb::AttachmentMetadataRecord* record = attachment_metadata.add_record();
   sync_pb::AttachmentIdProto attachment_id_proto =
-      syncer::CreateAttachmentIdProto(0, 0);
+      syncer::CreateAttachmentIdProto();
   *record->mutable_id() = attachment_id_proto;
 
   // Create two entries, each referencing the attachment.
@@ -1771,7 +1771,7 @@
 
 TEST_F(SyncableDirectoryTest, Directory_GetAttachmentIdsToUpload) {
   // Create one attachment, referenced by two entries.
-  AttachmentId attachment_id = AttachmentId::Create(0, 0);
+  AttachmentId attachment_id = AttachmentId::Create();
   sync_pb::AttachmentIdProto attachment_id_proto = attachment_id.GetProto();
   sync_pb::AttachmentMetadata attachment_metadata;
   sync_pb::AttachmentMetadataRecord* record = attachment_metadata.add_record();