[Media Router] Parse device description xml in utility process

chrome/browser/media/router/discovery/safe_dial_device_description_parser.h

+// Copyright 2017 The Chromium Authors. All rights reserved.

[imcheng, 2017/03/22 00:31:46]

Seems like this file should be in c/b/m/r/discovery/dial to be consistent with
https://codereview.chromium.org/2756483007

[zhaobin, 2017/03/22 01:55:32]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_
+
+#include "base/callback.h"

[imcheng, 2017/03/22 00:31:46]

#include <memory>
#include <string>

[zhaobin, 2017/03/22 01:55:32]

Done.

+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/optional.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/common/media_router/dial_device_description.h"
+#include "chrome/common/media_router/dial_device_description_parser.mojom.h"
+#include "content/public/browser/utility_process_mojo_client.h"
+
+namespace media_router {
+
+// SafeDialDeviceDescriptionParser parses the given device description XML file
+// safely via a utility process. This class runs on IO thread.
+class SafeDialDeviceDescriptionParser
+    : public base::RefCounted<SafeDialDeviceDescriptionParser> {

[imcheng, 2017/03/22 00:31:46]

why does this need to be ref counted?

[zhaobin, 2017/03/22 01:55:32]

Done.

+ public:
+  // Callback function to be invoked when utility process finishes parsing
+  // device description XML.
+  // |result|: returns false if parsing fails.

[imcheng, 2017/03/22 00:31:47]

s/result/success

[zhaobin, 2017/03/22 01:55:32]

Done.

+  // |device_description|: device description object. Empty if parsing fails.
+  using DeviceDescriptionCallback = base::Callback<void(
+      bool result,
+      const base::Optional<media_router::DialDeviceDescription>&
+          device_description)>;
+
+  SafeDialDeviceDescriptionParser();
+
+  // Start parsing device description XML file in utility process.
+  void Start(const std::string& xml_text,
+             const DeviceDescriptionCallback& callback);
+
+ private:
+  friend class base::RefCounted<SafeDialDeviceDescriptionParser>;
+
+  ~SafeDialDeviceDescriptionParser();
+
+  // See SafeDialDeviceDescriptionParser::DeviceDescriptionCallback
+  void OnParseDeviceDescriptionComplete(
+      bool result,

[imcheng, 2017/03/22 00:31:46]

s/result/success

[zhaobin, 2017/03/22 01:55:32]

Done.

+      const base::Optional<media_router::DialDeviceDescription>&
+          device_description);
+
+  // TODO(crbug.com/702766): Add an enum type describing why utility process
+  // fails to parse device description xml.
+  void OnParseDeviceDescriptionFailed();
+
+  // Utility client used to send device description parsing task to the utility
+  // process.
+  std::unique_ptr<content::UtilityProcessMojoClient<
+      chrome::mojom::DialDeviceDescriptionParser>>
+      utility_process_mojo_client_;
+
+  // Only accessed on the IO thread.
+  DeviceDescriptionCallback device_description_callback_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(SafeDialDeviceDescriptionParser);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_