[BlobAsync] Disk support for blob storage

storage/browser/blob/shareable_blob_data_item.h

Index: storage/browser/blob/shareable_blob_data_item.h
diff --git a/storage/browser/blob/shareable_blob_data_item.h b/storage/browser/blob/shareable_blob_data_item.h
index b356c0c78a13f465456c0ff12d7fcaff7103ff77..e5e6e7e14107fce2e5ba9a0e3bd09ae993178e6a 100644
--- a/storage/browser/blob/shareable_blob_data_item.h
+++ b/storage/browser/blob/shareable_blob_data_item.h
@@ -25,8 +25,8 @@ class InternalBlobData;
 // The data in this class (the item) is immutable, but the item itself can be
 // swapped out with an item with the same data but a different backing (think
 // RAM vs file backed).
-// We also allow the storage of a deletion closure which is used for memory
-// quota reclamation.
+// We also allow the storage of a memory quota allocation objeect which is used
+// for memory quota reclamation.
 class STORAGE_EXPORT ShareableBlobDataItem
     : public base::RefCounted<ShareableBlobDataItem> {
  public:
@@ -44,11 +44,10 @@ class STORAGE_EXPORT ShareableBlobDataItem
     POPULATED_WITHOUT_QUOTA
   };
 
-  ShareableBlobDataItem(const std::string& referencing_blob_uuid,
-                        scoped_refptr<BlobDataItem> item,
-                        State state);
+  ShareableBlobDataItem(scoped_refptr<BlobDataItem> item, State state);
 
   const scoped_refptr<BlobDataItem>& item() const { return item_; }
+
   void set_item(scoped_refptr<BlobDataItem> item);
 
   // This is a unique auto-incrementing id assigned to this item on
@@ -77,6 +76,7 @@ class STORAGE_EXPORT ShareableBlobDataItem
  private:
   friend class BlobMemoryController;
   friend class BlobMemoryControllerTest;
+  friend class BlobStorageContext;
   friend class base::RefCounted<ShareableBlobDataItem>;
   friend STORAGE_EXPORT void PrintTo(const ShareableBlobDataItem& x,
                                      ::std::ostream* os);
@@ -88,6 +88,8 @@ class STORAGE_EXPORT ShareableBlobDataItem
     memory_allocation_ = std::move(allocation);
   }
 
+  bool has_memory_allocation() { return static_cast<bool>(memory_allocation_); }
+
   // This is a unique identifier for this ShareableBlobDataItem.
   const uint64_t item_id_;
   State state_;