Update Commit and GetUpdatesResponse messages to include attachment ids.

sync/engine/commit_util.cc

Index: sync/engine/commit_util.cc
diff --git a/sync/engine/commit_util.cc b/sync/engine/commit_util.cc
index ad29e4f40dda11a2b46b8f04ddfe1493d03d92a9..c913edd11108c99e159fee7a7ad6536356facf1d 100644
--- a/sync/engine/commit_util.cc
+++ b/sync/engine/commit_util.cc
@@ -11,6 +11,7 @@
 
 #include "base/strings/string_util.h"
 #include "sync/engine/syncer_proto_util.h"
+#include "sync/internal_api/public/base/attachment_id_proto.h"
 #include "sync/internal_api/public/base/unique_position.h"
 #include "sync/protocol/bookmark_specifics.pb.h"
 #include "sync/protocol/sync.pb.h"
@@ -83,6 +84,7 @@ void AddClientConfigParamsToMessage(
 }
 
 namespace {
+
 void SetEntrySpecifics(const Entry& meta_entry,
                        sync_pb::SyncEntity* sync_entry) {
   // Add the new style extension and the folder bit.
@@ -92,6 +94,16 @@ void SetEntrySpecifics(const Entry& meta_entry,
   CHECK(!sync_entry->specifics().password().has_client_only_encrypted_data());
   DCHECK_EQ(meta_entry.GetModelType(), GetModelType(*sync_entry));
 }
+
+void SetAttachmentIds(const Entry& meta_entry,
+                      sync_pb::SyncEntity* sync_entry) {
+  const sync_pb::AttachmentMetadata& attachment_metadata =
+      meta_entry.GetAttachmentMetadata();
+  for (int i = 0; i < attachment_metadata.record_size(); ++i) {
+    *sync_entry->add_attachment_id() = attachment_metadata.record(i).id();
+  }
+}
+
 }  // namespace
 
 void BuildCommitItem(
@@ -161,6 +173,8 @@ void BuildCommitItem(
   sync_entry->set_ctime(TimeToProtoTime(meta_entry.GetCtime()));
   sync_entry->set_mtime(TimeToProtoTime(meta_entry.GetMtime()));
 
+  SetAttachmentIds(meta_entry, sync_entry);
+
   // Handle bookmarks separately.
   if (meta_entry.GetSpecifics().has_bookmark()) {
     if (meta_entry.GetIsDel()) {
@@ -305,6 +319,8 @@ void UpdateServerFieldsAfterCommit(
       (committed_entry.folder() ||
        committed_entry.bookmarkdata().bookmark_folder()));
   local_entry->PutServerSpecifics(committed_entry.specifics());
+  local_entry->PutServerAttachmentMetadata(
+      CreateAttachmentMetadata(committed_entry.attachment_id()));
   local_entry->PutServerMtime(ProtoTimeToTime(committed_entry.mtime()));
   local_entry->PutServerCtime(ProtoTimeToTime(committed_entry.ctime()));
   if (committed_entry.has_unique_position()) {