[Storage] Blob Storage Refactoring pt 1

storage/browser/blob/blob_data_snapshot.h

+// TODO: Insert description here. (generated by dmurph)
+
+#ifndef STORAGE_BROWSER_BLOB_BLOB_DATA_SNAPSHOT_H_
+#define STORAGE_BROWSER_BLOB_BLOB_DATA_SNAPSHOT_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/supports_user_data.h"
+#include "storage/browser/blob/blob_data_item.h"
+#include "storage/browser/storage_browser_export.h"
+
+namespace storage {
+class BlobDataBuilder;
+
+// Snapshot of a Blob. This snapshot holds a refcount of the current
+// blob item resources so the backing storage for these items will stick
+// around for the lifetime of this object. (The data represented by a blob is
+// immutable, but the backing store can change). This structure thread safe.
+class STORAGE_EXPORT BlobDataSnapshot : public base::SupportsUserData::Data {
+ public:
+  BlobDataSnapshot(const BlobDataSnapshot& other);
+  ~BlobDataSnapshot() override;
+
+  const std::string& uuid() const { return uuid_; }

[michaeln, 2015/01/22 02:26:34]

A snapshot may outlive the registered blob, so this uuid isn't guaranteed to be
good. It may make sense for this class to internally own BlobDataHandle ensure
the uuid doesn't go away either?

[dmurph, 2015/01/23 00:10:18]

As discussed, removed the uuid here, and clarified responsibilites.

+  const std::vector<scoped_refptr<BlobDataItem>>& items() const {
+    return items_;
+  }
+  const std::string& content_type() const { return content_type_; }
+  const std::string& content_disposition() const {
+    return content_disposition_;
+  }
+  size_t GetMemoryUsage() const;
+
+ private:
+  friend class BlobDataBuilder;
+  BlobDataSnapshot(const std::string& uuid,
+                   const std::string& content_type,
+                   const std::string& content_disposition,
+                   const std::vector<scoped_refptr<BlobDataItem>>& items);
+
+  const std::string uuid_;
+  const std::string content_type_;
+  const std::string content_disposition_;
+  const std::vector<scoped_refptr<BlobDataItem>> items_;
+};
+
+}  // namespace storage
+#endif  // STORAGE_BROWSER_BLOB_BLOB_DATA_SNAPSHOT_H_