Split up streams logic to prepare for PlzNavigate RDH changes.

content/browser/loader/stream_writer.cc

+// Copyright 2014 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 "content/browser/loader/stream_writer.h"
+
+#include "base/guid.h"
+#include "content/browser/streams/stream.h"
+#include "content/browser/streams/stream_registry.h"
+#include "content/public/browser/resource_controller.h"
+#include "net/base/io_buffer.h"
+#include "url/gurl.h"
+#include "url/url_constants.h"
+
+namespace content {
+
+StreamWriter::StreamWriter() : controller_(nullptr) {
+}
+
+StreamWriter::~StreamWriter() {
+  if (stream_.get())
+    Finalize();
+}
+
+void StreamWriter::InitializeStream(StreamRegistry* registry,
+                                    const GURL& origin) {
+  DCHECK(!stream_.get());
+
+  // TODO(tyoshino): Find a way to share this with the blob URL creation in
+  // WebKit.
+  GURL url(std::string(url::kBlobScheme) + ":" + origin.spec() +
+           base::GenerateGUID());
+  stream_ = new Stream(registry, this, url);
+}
+
+void StreamWriter::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                              int* buf_size,
+                              int min_size) {
+  static const int kReadBufSize = 32768;
+
+  DCHECK(buf);

[mmenke, 2014/10/15 20:05:44]

include base/logging.h for DCHECK

+  DCHECK(buf_size);
+  DCHECK_LE(min_size, kReadBufSize);
+  if (!read_buffer_.get())
+    read_buffer_ = new net::IOBuffer(kReadBufSize);
+  *buf = read_buffer_.get();
+  *buf_size = kReadBufSize;
+}
+
+void StreamWriter::OnReadCompleted(int bytes_read, bool* defer) {
+  if (!bytes_read)
+    return;
+
+  // We have more data to read.

[mmenke, 2014/10/15 20:05:44]

While you're here, shouldn't use "we" in comments.

+  DCHECK(read_buffer_.get());
+
+  // Release the ownership of the buffer, and store a reference
+  // to it. A new one will be allocated in OnWillRead().
+  scoped_refptr<net::IOBuffer> buffer;
+  read_buffer_.swap(buffer);
+  stream_->AddData(buffer, bytes_read);
+
+  if (!stream_->can_add_data())
+    *defer = true;
+}
+
+void StreamWriter::Finalize() {
+  DCHECK(stream_.get());
+  stream_->Finalize();
+  stream_->RemoveWriteObserver(this);
+  stream_ = nullptr;
+}
+
+void StreamWriter::OnSpaceAvailable(Stream* stream) {
+  controller_->Resume();
+}
+
+void StreamWriter::OnClose(Stream* stream) {
+  controller_->Cancel();
+}
+
+}  // namespace content