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

storage/browser/blob/upload_blob_element_reader.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/upload_blob_element_reader.h"
-
-#include "net/base/net_errors.h"
-#include "storage/browser/blob/blob_data_handle.h"
-#include "storage/browser/blob/blob_reader.h"
-
-namespace storage {
-
-UploadBlobElementReader::UploadBlobElementReader(
-    scoped_ptr<storage::BlobReader> reader,
-    scoped_ptr<BlobDataHandle> handle)
-    : reader_(reader.Pass()), handle_(handle.Pass()) {}
-
-UploadBlobElementReader::~UploadBlobElementReader() {}
-
-int UploadBlobElementReader::Init(const net::CompletionCallback& callback) {
-  BlobReader::Status status = reader_->CalculateSize(callback);
-  switch (status) {
-    case BlobReader::Status::NET_ERROR:
-      return reader_->net_error();
-    case BlobReader::Status::IO_PENDING:
-      return net::ERR_IO_PENDING;
-    case BlobReader::Status::DONE:
-      return net::OK;
-  }
-  NOTREACHED();
-  return net::ERR_FAILED;
-}
-
-uint64_t UploadBlobElementReader::GetContentLength() const {
-  return reader_->total_size();
-}
-
-uint64_t UploadBlobElementReader::BytesRemaining() const {
-  return reader_->remaining_bytes();
-}
-
-bool UploadBlobElementReader::IsInMemory() const {
-  return reader_->IsInMemory();
-}
-
-int UploadBlobElementReader::Read(net::IOBuffer* buf,
-                                  int buf_length,
-                                  const net::CompletionCallback& callback) {
-  int length = 0;
-  BlobReader::Status status = reader_->Read(buf, buf_length, &length, callback);
-  switch (status) {
-    case BlobReader::Status::NET_ERROR:
-      return reader_->net_error();
-    case BlobReader::Status::IO_PENDING:
-      return net::ERR_IO_PENDING;
-    case BlobReader::Status::DONE:
-      return length;
-  }
-  NOTREACHED();
-  return net::ERR_FAILED;
-}
-
-const std::string& UploadBlobElementReader::uuid() const {
-  return handle_->uuid();
-}
-
-}  // namespace storage