Revert of [Blob] BlobReader class & tests, and removal of all redundant reading.

storage/browser/blob/upload_blob_element_reader.h

-// 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.
-
-#ifndef STORAGE_BROWSER_BLOB_UPLOAD_BLOB_ELEMENT_READER_H_
-#define STORAGE_BROWSER_BLOB_UPLOAD_BLOB_ELEMENT_READER_H_
-
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "net/base/completion_callback.h"
-#include "net/base/upload_element_reader.h"
-#include "storage/browser/storage_browser_export.h"
-
-namespace net {
-class IOBuffer;
-}
-
-namespace storage {
-class BlobDataHandle;
-class BlobReader;
-
-// This class is a wrapper around the BlobReader to make it conform
-// to the net::UploadElementReader interface, and it also holds around the
-// handle to the blob so it stays in memory while we read it.
-class STORAGE_EXPORT UploadBlobElementReader
-    : NON_EXPORTED_BASE(public net::UploadElementReader) {
- public:
-  UploadBlobElementReader(scoped_ptr<BlobReader> reader,
-                          scoped_ptr<BlobDataHandle> handle);
-  ~UploadBlobElementReader() override;
-
-  int Init(const net::CompletionCallback& callback) override;
-
-  uint64_t GetContentLength() const override;
-
-  uint64_t BytesRemaining() const override;
-
-  bool IsInMemory() const override;
-
-  int Read(net::IOBuffer* buf,
-           int buf_length,
-           const net::CompletionCallback& callback) override;
-
-  const std::string& uuid() const;
-
- private:
-  scoped_ptr<BlobReader> reader_;
-  scoped_ptr<BlobDataHandle> handle_;
-
-  DISALLOW_COPY_AND_ASSIGN(UploadBlobElementReader);
-};
-
-}  // namespace storage
-#endif  // STORAGE_BROWSER_BLOB_UPLOAD_BLOB_ELEMENT_READER_H_