Update sync API to support attachments.

sync/api/attachments/attachment_id.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/api/attachments/attachment_id.h"
 
 #include "base/logging.h"
 #include "base/rand_util.h"
+#include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 
+void AttachmentId::ImmutableAttachmentIdProtoTraits::InitializeWrapper(
+    Wrapper* wrapper) {
+  *wrapper = new sync_pb::AttachmentIdProto();
+}
+
+void AttachmentId::ImmutableAttachmentIdProtoTraits::DestroyWrapper(
+    Wrapper* wrapper) {
+  delete *wrapper;
+}
+
+const sync_pb::AttachmentIdProto&
+AttachmentId::ImmutableAttachmentIdProtoTraits::Unwrap(const Wrapper& wrapper) {
+  return *wrapper;
+}
+
+sync_pb::AttachmentIdProto*
+AttachmentId::ImmutableAttachmentIdProtoTraits::UnwrapMutable(
+    Wrapper* wrapper) {
+  return *wrapper;
+}
+
+void AttachmentId::ImmutableAttachmentIdProtoTraits::Swap(
+    sync_pb::AttachmentIdProto* t1,
+    sync_pb::AttachmentIdProto* t2) {
+  t1->Swap(t2);
+}
+
 AttachmentId::~AttachmentId() {}
 
 bool AttachmentId::operator==(const AttachmentId& other) const {
-  return unique_id_ == other.unique_id_;
+  return proto_.Get().unique_id() == other.proto_.Get().unique_id();
 }
 
 bool AttachmentId::operator!=(const AttachmentId& other) const {
   return !operator==(other);
 }
 
 bool AttachmentId::operator<(const AttachmentId& other) const {
-  return unique_id_ < other.unique_id_;
+  return proto_.Get().unique_id() < other.proto_.Get().unique_id();
 }
 
 // Static.
 AttachmentId AttachmentId::Create() {
   // Only requirement here is that this id must be globally unique.
   // TODO(maniscalco): Consider making this base64 encoded.
-  return AttachmentId(base::RandBytesAsString(16));
+  sync_pb::AttachmentIdProto proto;
+  proto.set_unique_id(base::RandBytesAsString(16));
+  return AttachmentId(&proto);
 }
 
-AttachmentId::AttachmentId(const std::string& unique_id)
-    : unique_id_(unique_id) {
-  DCHECK(!unique_id_.empty());
+// Static.
+AttachmentId AttachmentId::CreateFromProto(
+    const sync_pb::AttachmentIdProto& proto) {
+  sync_pb::AttachmentIdProto copy_of_proto(proto);
+  return AttachmentId(&copy_of_proto);
 }
 
+const sync_pb::AttachmentIdProto& AttachmentId::GetProto() const {
+  return proto_.Get();
+}
+
+AttachmentId::AttachmentId(sync_pb::AttachmentIdProto* proto)
+    : proto_(proto) {}
+
 }  // namespace syncer