Revert of Keep track of which attachments are referenced by which sync entries.

sync/internal_api/base_node.cc

Index: sync/internal_api/base_node.cc
diff --git a/sync/internal_api/base_node.cc b/sync/internal_api/base_node.cc
index 57dbb22f72115e58dd8221f769afe2baf78bf5fc..078839540e3e66c4a9bfeb5ccd32646fa86410b6 100644
--- a/sync/internal_api/base_node.cc
+++ b/sync/internal_api/base_node.cc
@@ -291,13 +291,10 @@
 }
 
 const syncer::AttachmentIdList BaseNode::GetAttachmentIds() const {
-  AttachmentIdList result;
-  const sync_pb::AttachmentMetadata& metadata =
-      GetEntry()->GetAttachmentMetadata();
-  for (int i = 0; i < metadata.record_size(); ++i) {
-    result.push_back(AttachmentId::CreateFromProto(metadata.record(i).id()));
-  }
-  return result;
+  // TODO(maniscalco): Once EntryKernel is capable of storing AttachmentIds,
+  // update this method to retrieve the list of AttachmentIds from read_node and
+  // pass it to CreateRemoteData (bug 348625).
+  return AttachmentIdList();
 }
 
 void BaseNode::SetUnencryptedSpecifics(