[BlobAsync] Disk support for blob storage

storage/browser/blob/shareable_blob_data_item.cc

 // Copyright 2015 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 "storage/browser/blob/shareable_blob_data_item.h"
 
 #include "storage/browser/blob/blob_data_item.h"
 
 namespace storage {
 namespace {
 
 uint64_t GetAndIncrementItemId() {
   static uint64_t sNextItemId = 0;
   return sNextItemId++;
 }
 
 }  // namespace
 
 ShareableBlobDataItem::ShareableBlobDataItem(
-    const std::string& referencing_blob_uuid,
     scoped_refptr<BlobDataItem> item,
     ShareableBlobDataItem::State state)
     : item_id_(GetAndIncrementItemId()), state_(state), item_(std::move(item)) {
   DCHECK_NE(item_->type(), DataElement::TYPE_BLOB);
-  referencing_blobs_.insert(referencing_blob_uuid);
 }
 
 ShareableBlobDataItem::~ShareableBlobDataItem() {
 }
 
 void ShareableBlobDataItem::set_item(scoped_refptr<BlobDataItem> item) {
   item_ = std::move(item);
 }
 
 void PrintTo(const ShareableBlobDataItem& x, ::std::ostream* os) {
@@ skipping 12 matching lines @@
   return a.item_id() == b.item_id() && *a.item() == *b.item() &&
          a.referencing_blobs() == b.referencing_blobs();
 }
 
 bool operator!=(const ShareableBlobDataItem& a,
                 const ShareableBlobDataItem& b) {
   return !(a == b);
 }
 
 }  // namespace storage