Implement AssetLinkRetriever for Asset Links in Chrome.

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

+// 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.
+
+#include "components/password_manager/core/browser/site_affiliation/asset_link_retriever.h"
+
+#include <utility>
+
+#include "base/logging.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_status_code.h"
+#include "net/traffic_annotation/network_traffic_annotation.h"
+#include "net/url_request/url_fetcher.h"
+
+namespace password_manager {
+
+AssetLinkRetriever::AssetLinkRetriever(GURL file_url)
+    : url_(std::move(file_url)), state_(State::INACTIVE), error_(false) {
+  DCHECK(url_.is_valid());
+  DCHECK(url_.SchemeIs(url::kHttpsScheme));
+}
+
+void AssetLinkRetriever::Start(net::URLRequestContextGetter* context_getter) {
+  if (state_ != State::INACTIVE)
+    return;
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("asset_links", R"(
+        semantics {
+          sender: "Asset Links Fetcher"
+          description:
+            "The asset links is a JSON file hosted on "
+            "https://<domain>/.well-known/assetlinks.json. It contains "
+            "different permissions the site gives to apps/other sites. Chrome "
+            "looks for a permission to delegate the credentials from the site "
+            "to another domain. It's used for handling the stored credentials "
+            "in the password manager."
+          trigger:
+            "Load a site where it's possible to sign-in. The site can have a "
+            "password form or use the Credential Management API."
+          data: "None."
+          destination: WEBSITE
+        }
+        policy {
+          cookies_allowed: false
+          setting: "No setting"
+          policy_exception_justification:
+            "The file is considered to be a resource of the page loaded."
+        })");
+  fetcher_ = net::URLFetcher::Create(url_, net::URLFetcher::GET, this,
+                                     traffic_annotation);
+  fetcher_->SetRequestContext(context_getter);
+  fetcher_->SetLoadFlags(
+      net::LOAD_DO_NOT_SEND_COOKIES | net::LOAD_DO_NOT_SAVE_COOKIES |
+      net::LOAD_DO_NOT_SEND_AUTH_DATA | net::LOAD_MAYBE_USER_GESTURE);
+  fetcher_->SetStopOnRedirect(true);
+  fetcher_->Start();
+  state_ = State::NETWORK_REQUEST;
+}
+
+AssetLinkRetriever::~AssetLinkRetriever() = default;
+
+void AssetLinkRetriever::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK(source == fetcher_.get());
+
+  error_ = !source->GetStatus().is_success() ||
+           source->GetResponseCode() != net::HTTP_OK;
+  if (error_) {
+    state_ = State::FINISHED;
+  } else {
+    // TODO(crbug.com/630555): Start parsing here.
+  }
+  fetcher_.reset();
+}
+
+}  // namespace password_manager