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

sync/internal_api/attachments/on_disk_attachment_store.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/internal_api/public/attachments/on_disk_attachment_store.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 301 matching lines @@
   std::string data_str;
   leveldb::Status status = db_->Get(
       MakeNonCachingReadOptions(), key, &data_str);
   if (!status.ok()) {
     DVLOG(1) << "DB::Get for data failed: status=" << status.ToString();
     return attachment.Pass();
   }
   scoped_refptr<base::RefCountedMemory> data =
       base::RefCountedString::TakeString(&data_str);
   uint32_t crc32c = ComputeCrc32c(data);
-  if (record_metadata.has_crc32c()) {
-    if (record_metadata.crc32c() != crc32c) {
-      DVLOG(1) << "Attachment crc32c does not match value read from store";
-      return attachment.Pass();
-    }
-    if (record_metadata.crc32c() != attachment_id.GetCrc32c()) {
-      DVLOG(1) << "Attachment crc32c does not match value in AttachmentId";
-      return attachment.Pass();
-    }
+  if (record_metadata.has_crc32c() && record_metadata.crc32c() != crc32c) {
+    DVLOG(1) << "Attachment crc does not match";
+    return attachment.Pass();
   }
   attachment.reset(
-      new Attachment(Attachment::CreateFromParts(attachment_id, data)));
+      new Attachment(Attachment::CreateFromParts(attachment_id, data, crc32c)));
   return attachment.Pass();
 }
 
 bool OnDiskAttachmentStore::WriteSingleAttachment(
     const Attachment& attachment) {
   const std::string metadata_key =
       MakeMetadataKeyFromAttachmentId(attachment.GetId());
   const std::string data_key = MakeDataKeyFromAttachmentId(attachment.GetId());
 
   std::string metadata_str;
@@ skipping 62 matching lines @@
   return key;
 }
 
 AttachmentMetadata OnDiskAttachmentStore::MakeAttachmentMetadata(
     const AttachmentId& attachment_id,
     const attachment_store_pb::RecordMetadata& record_metadata) {
   return AttachmentMetadata(attachment_id, record_metadata.attachment_size());
 }
 
 }  // namespace syncer