Implement AssetLinkRetriever for Asset Links in Chrome.

components/password_manager/core/browser/site_affiliation/asset_link_retriever.h

+// Copyright 2017 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 COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_SITE_AFFILIATION_ASSET_LINK_RETRIEVER_H_
+#define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_SITE_AFFILIATION_ASSET_LINK_RETRIEVER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "url/gurl.h"
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace password_manager {
+
+// The class is responsible for fetching and parsing the digit asset links file.
+// The file is a JSON containing different directives for the domain. The class
+// is only interested in those related to credentials delegations.
+// The spec is
+// https://github.com/google/digitalassetlinks/blob/master/well-known/details.md
+class AssetLinkRetriever : public base::RefCounted<AssetLinkRetriever>,

[vabr (Chromium), 2017/06/18 16:37:51]

Why does this need to be refcounted? Does net::URLFetcher::Create expect that?

[vasilii, 2017/06/19 12:20:20]

This is a part of a bigger plan. If two requests require the same file then this
object should be shared between them.
E.g. ru.aliexpress.com/.well-known/assetlinks.json includes
https://m.aliexpress.com/.well-known/assetlinks.json. Once we read it we need to
make sure that https://www.aliexpress.com also doesn't mind to give its
credentials to ru.aliexpress.com. But it includes the same file we just read.

[vabr (Chromium), 2017/06/19 13:07:54]

Acknowledged.

+                           public net::URLFetcherDelegate {
+ public:
+  enum class State {
+    INACTIVE,
+    NETWORK_REQUEST,
+    FINISHED,
+  };
+
+  AssetLinkRetriever(GURL file_url);

[vabr (Chromium), 2017/06/18 16:37:51]

Should this be explicit?

[vasilii, 2017/06/19 12:20:20]

Done.

+
+  // Starts a network request if the current state is INACTIVE. All the calls
+  // afterwards are ignored.
+  void Start(net::URLRequestContextGetter* context_getter);
+
+  State state() const { return state_; }
+
+  bool error() const { return error_; }
+
+ private:
+  friend class base::RefCounted<AssetLinkRetriever>;
+  ~AssetLinkRetriever() override;
+
+  // net::URLFetcherDelegate:
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
+
+  // URL of the file retrieved.
+  const GURL url_;
+
+  // Current state of the retrieval.
+  State state_;
+
+  // Whether the reading finished with error.
+  bool error_;
+
+  std::unique_ptr<net::URLFetcher> fetcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(AssetLinkRetriever);
+};
+
+}  // namespace password_manager
+#endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_SITE_AFFILIATION_ASSET_LINK_RETRIEVER_H_