Use mojo for Chrome Loading, Part 1

content/browser/loader/mojo_async_resource_handler.h

Index: content/browser/loader/mojo_async_resource_handler.h
diff --git a/content/browser/loader/mojo_async_resource_handler.h b/content/browser/loader/mojo_async_resource_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..64e6513577a56048ed2faaf4f2bd98ba6cc0b344
--- /dev/null
+++ b/content/browser/loader/mojo_async_resource_handler.h
@@ -0,0 +1,83 @@
+// Copyright 2016 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 CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_
+#define CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/timer/timer.h"
+#include "content/browser/loader/resource_handler.h"
+#include "content/common/url_loader.mojom.h"
+#include "mojo/message_pump/handle_watcher.h"
+#include "mojo/public/cpp/system/data_pipe.h"
+#include "net/base/io_buffer.h"
+#include "url/gurl.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace content {
+class ResourceDispatcherHostImpl;
+
+// Used to complete an asynchronous resource request in response to resource
+// load events from the resource dispatcher host. This class is used only
+// when LoadingWithMojo runtime enabled flag is enabled.

[mmenke, 2016/05/26 21:46:09]

Could you add TODOs about what this does not yet supports:  upload progress,
redirects, download to file, move histograms over, set zoom level (Which doesn't
really seem to belong at this layer), send cached metadata...I think that's it?

[yhirano, 2016/05/27 11:30:34]

Done.

+class MojoAsyncResourceHandler : public ResourceHandler {
+ public:
+  MojoAsyncResourceHandler(net::URLRequest* request,
+                           ResourceDispatcherHostImpl* rdh,
+                           std::unique_ptr<mojom::URLLoader> url_loader,
+                           mojom::URLLoaderClientPtr url_loader_client);
+  ~MojoAsyncResourceHandler() override;
+
+  // ResourceHandler implementation:
+  bool OnRequestRedirected(const net::RedirectInfo& redirect_info,
+                           ResourceResponse* response,
+                           bool* defer) override;
+  bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
+  bool OnWillStart(const GURL& url, bool* defer) override;
+  bool OnBeforeNetworkStart(const GURL& url, bool* defer) override;
+  bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                  int* buf_size,
+                  int min_size) override;
+  bool OnReadCompleted(int bytes_read, bool* defer) override;
+  void OnResponseCompleted(const net::URLRequestStatus& status,
+                           const std::string& security_info,
+                           bool* defer) override;
+  void OnDataDownloaded(int bytes_downloaded) override;
+
+ private:
+  // IPC message handlers:
+  void OnFollowRedirect(int request_id);
+
+  void ResumeIfDeferred();
+  void OnDefer();
+  bool CheckForSufficientResource();
+  void OnWritable(MojoResult result);
+
+  ResourceDispatcherHostImpl* rdh_;
+
+  bool did_defer_ = false;
+  bool has_checked_for_sufficient_resources_ = false;
+  bool sent_received_response_message_ = false;
+  base::TimeTicks response_started_ticks_;
+
+  mojo::ScopedDataPipeProducerHandle writer_;
+  mojo::common::HandleWatcher handle_watcher_;
+  std::unique_ptr<mojom::URLLoader> url_loader_;
+  mojom::URLLoaderClientPtr url_loader_client_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoAsyncResourceHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_