[remoting] Add stream request support to ProtobufHttpStatus

* Add stream request support to ProtobufHttpStatus, which includes some
  refactoring in the code.
* Make ProtobufHttpClient directly own the requests, to make lifetime
  managing less painful.

Bug: 1103416
Change-Id: I9c1f62acb4e02cd968387bc4cc34db8dd6268c25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2299536
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790112}

remoting/base/BUILD.gn

@@ -33,10 +33,16 @@ source_set("base") {
     "protobuf_http_client.h",
     "protobuf_http_request.cc",
     "protobuf_http_request.h",
+    "protobuf_http_request_base.cc",
+    "protobuf_http_request_base.h",
+    "protobuf_http_request_config.cc",
+    "protobuf_http_request_config.h",
     "protobuf_http_status.cc",
     "protobuf_http_status.h",
     "protobuf_http_stream_parser.cc",
     "protobuf_http_stream_parser.h",
+    "protobuf_http_stream_request.cc",
+    "protobuf_http_stream_request.h",
     "rate_counter.cc",
     "rate_counter.h",
     "result.h",

remoting/base/protobuf_http_client.cc

@@ -8,7 +8,8 @@
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "remoting/base/oauth_token_getter.h"
-#include "remoting/base/protobuf_http_request.h"
+#include "remoting/base/protobuf_http_request_base.h"
+#include "remoting/base/protobuf_http_request_config.h"
 #include "remoting/base/protobuf_http_status.h"
 #include "services/network/public/cpp/resource_request.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
@@ -19,7 +20,6 @@
 namespace {
 
 constexpr char kAuthorizationHeaderFormat[] = "Authorization: Bearer %s";
-constexpr int kMaxResponseSizeKb = 512;
 
 }  // namespace
 
@@ -33,15 +33,15 @@ ProtobufHttpClient::ProtobufHttpClient(
       token_getter_(token_getter),
       url_loader_factory_(url_loader_factory) {}
 
-ProtobufHttpClient::~ProtobufHttpClient() = default;
+ProtobufHttpClient::~ProtobufHttpClient() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+}
 
 void ProtobufHttpClient::ExecuteRequest(
-    std::unique_ptr<ProtobufHttpRequest> request) {
-  DCHECK(request->request_message);
-  DCHECK(!request->path.empty());
-  DCHECK(request->response_callback_);
+    std::unique_ptr<ProtobufHttpRequestBase> request) {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-  if (!request->authenticated) {
+  if (!request->config().authenticated) {
     DoExecuteRequest(std::move(request), OAuthTokenGetter::Status::SUCCESS, {},
                      {});
     return;
@@ -54,23 +54,37 @@ void ProtobufHttpClient::ExecuteRequest(
 }
 
 void ProtobufHttpClient::CancelPendingRequests() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
   weak_factory_.InvalidateWeakPtrs();
+  pending_requests_.clear();
+}
+
+bool ProtobufHttpClient::HasPendingRequests() const {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
+  return !pending_requests_.empty();
 }
 
 void ProtobufHttpClient::DoExecuteRequest(
-    std::unique_ptr<ProtobufHttpRequest> request,
+    std::unique_ptr<ProtobufHttpRequestBase> request,
     OAuthTokenGetter::Status status,
     const std::string& user_email,
     const std::string& access_token) {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
   if (status != OAuthTokenGetter::Status::SUCCESS) {
-    LOG(ERROR) << "Failed to fetch access token. Status: " << status;
-    request->OnResponse(
-        ProtobufHttpStatus(net::HttpStatusCode::HTTP_UNAUTHORIZED), nullptr);
+    std::string error_message =
+        base::StringPrintf("Failed to fetch access token. Status: %d", status);
+    LOG(ERROR) << error_message;
+    request->OnAuthFailed(ProtobufHttpStatus(
+        ProtobufHttpStatus::Code::UNAUTHENTICATED, error_message));
     return;
   }
 
   auto resource_request = std::make_unique<network::ResourceRequest>();
-  resource_request->url = GURL("https://" + server_endpoint_ + request->path);
+  resource_request->url =
+      GURL("https://" + server_endpoint_ + request->config().path);
   resource_request->load_flags =
       net::LOAD_BYPASS_CACHE | net::LOAD_DISABLE_CACHE;
   resource_request->credentials_mode = network::mojom::CredentialsMode::kOmit;
@@ -85,35 +99,28 @@ void ProtobufHttpClient::DoExecuteRequest(
 
   std::unique_ptr<network::SimpleURLLoader> send_url_loader =
       network::SimpleURLLoader::Create(std::move(resource_request),
-                                       request->traffic_annotation);
-  send_url_loader->SetTimeoutDuration(request->timeout_duration);
+                                       request->config().traffic_annotation);
+  base::TimeDelta timeout_duration = request->GetRequestTimeoutDuration();
+  if (!timeout_duration.is_zero()) {
+    send_url_loader->SetTimeoutDuration(request->GetRequestTimeoutDuration());
+  }
   send_url_loader->AttachStringForUpload(
-      request->request_message->SerializeAsString(), "application/x-protobuf");
-  send_url_loader->DownloadToString(
-      url_loader_factory_.get(),
-      base::BindOnce(&ProtobufHttpClient::OnResponse,
-                     weak_factory_.GetWeakPtr(), std::move(request),
-                     std::move(send_url_loader)),
-      kMaxResponseSizeKb);
+      request->config().request_message->SerializeAsString(),
+      "application/x-protobuf");
+  auto* unowned_request = request.get();
+  base::OnceClosure invalidator = base::BindOnce(
+      &ProtobufHttpClient::CancelRequest, weak_factory_.GetWeakPtr(),
+      pending_requests_.insert(pending_requests_.end(), std::move(request)));
+  unowned_request->StartRequest(url_loader_factory_.get(),
+                                std::move(send_url_loader),
+                                std::move(invalidator));
 }
 
-void ProtobufHttpClient::OnResponse(
-    std::unique_ptr<ProtobufHttpRequest> request,
-    std::unique_ptr<network::SimpleURLLoader> url_loader,
-    std::unique_ptr<std::string> response_body) {
-  net::Error net_error = static_cast<net::Error>(url_loader->NetError());
-  if (net_error == net::Error::ERR_HTTP_RESPONSE_CODE_FAILURE &&
-      (!url_loader->ResponseInfo() || !url_loader->ResponseInfo()->headers)) {
-    LOG(ERROR) << "Can't find response header.";
-    net_error = net::Error::ERR_INVALID_RESPONSE;
-  }
-  ProtobufHttpStatus status =
-      (net_error == net::Error::ERR_HTTP_RESPONSE_CODE_FAILURE ||
-       net_error == net::Error::OK)
-          ? ProtobufHttpStatus(static_cast<net::HttpStatusCode>(
-                url_loader->ResponseInfo()->headers->response_code()))
-          : ProtobufHttpStatus(net_error);
-  request->OnResponse(status, std::move(response_body));
+void ProtobufHttpClient::CancelRequest(
+    const PendingRequestListIterator& request_iterator) {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
+  pending_requests_.erase(request_iterator);
 }
 
 }  // namespace remoting

remoting/base/protobuf_http_client.h

@@ -5,22 +5,23 @@
 #ifndef REMOTING_BASE_PROTOBUF_HTTP_CLIENT_H_
 #define REMOTING_BASE_PROTOBUF_HTTP_CLIENT_H_
 
+#include <list>
 #include <memory>
 #include <string>
 
 #include "base/memory/scoped_refptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/sequence_checker.h"
 #include "net/traffic_annotation/network_traffic_annotation.h"
 #include "remoting/base/oauth_token_getter.h"
 
 namespace network {
 class SharedURLLoaderFactory;
-class SimpleURLLoader;
 }  // namespace network
 
 namespace remoting {
 
-struct ProtobufHttpRequest;
+class ProtobufHttpRequestBase;
 
 // Helper class for executing REST/Protobuf requests over HTTP.
 class ProtobufHttpClient final {
@@ -38,26 +39,36 @@ class ProtobufHttpClient final {
 
   // Executes a unary request. Caller will not be notified of the result if
   // CancelPendingRequests() is called or |this| is destroyed.
-  void ExecuteRequest(std::unique_ptr<ProtobufHttpRequest> request);
+  void ExecuteRequest(std::unique_ptr<ProtobufHttpRequestBase> request);
 
-  // Tries to cancel all pending requests. Note that this prevents request
-  // callbacks from being called but does not necessarily stop pending requests
-  // from being sent.
+  // Cancel all pending requests.
   void CancelPendingRequests();
 
+  // Indicates whether the client has any pending requests.
+  bool HasPendingRequests() const;
+
  private:
-  void DoExecuteRequest(std::unique_ptr<ProtobufHttpRequest> request,
+  using PendingRequestList =
+      std::list<std::unique_ptr<ProtobufHttpRequestBase>>;
+
+  // std::list iterators are stable, so they survive list editing and only
+  // become invalidated when underlying element is deleted.
+  using PendingRequestListIterator = PendingRequestList::iterator;
+
+  void DoExecuteRequest(std::unique_ptr<ProtobufHttpRequestBase> request,
                         OAuthTokenGetter::Status status,
                         const std::string& user_email,
                         const std::string& access_token);
 
-  void OnResponse(std::unique_ptr<ProtobufHttpRequest> request,
-                  std::unique_ptr<network::SimpleURLLoader> url_loader,
-                  std::unique_ptr<std::string> response_body);
+  void CancelRequest(const PendingRequestListIterator& request_iterator);
 
   std::string server_endpoint_;
   OAuthTokenGetter* token_getter_;
   scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory_;
+  PendingRequestList pending_requests_;
+
+  SEQUENCE_CHECKER(sequence_checker_);
+
   base::WeakPtrFactory<ProtobufHttpClient> weak_factory_{this};
 };
 

remoting/base/protobuf_http_request.cc

@@ -4,19 +4,52 @@
 
 #include "remoting/base/protobuf_http_request.h"
 
+#include "remoting/base/protobuf_http_request_config.h"
+#include "services/network/public/cpp/simple_url_loader.h"
+#include "third_party/protobuf/src/google/protobuf/message_lite.h"
+
 namespace remoting {
 
+namespace {
+constexpr int kMaxResponseSizeKb = 512;
+}  // namespace
+
 ProtobufHttpRequest::ProtobufHttpRequest(
-    const net::NetworkTrafficAnnotationTag& traffic_annotation)
-    : traffic_annotation(traffic_annotation) {}
+    std::unique_ptr<ProtobufHttpRequestConfig> config)
+    : ProtobufHttpRequestBase(std::move(config)) {}
 
 ProtobufHttpRequest::~ProtobufHttpRequest() = default;
 
+void ProtobufHttpRequest::SetTimeoutDuration(base::TimeDelta timeout_duration) {
+  timeout_duration_ = timeout_duration;
+}
+
+void ProtobufHttpRequest::OnAuthFailed(const ProtobufHttpStatus& status) {
+  std::move(response_callback_).Run(status);
+}
+
+void ProtobufHttpRequest::StartRequestInternal(
+    network::mojom::URLLoaderFactory* loader_factory) {
+  DCHECK(response_callback_);
+
+  // Safe to use unretained as callback will not be called once |url_loader_| is
+  // deleted.
+  url_loader_->DownloadToString(
+      loader_factory,
+      base::BindOnce(&ProtobufHttpRequest::OnResponse, base::Unretained(this)),
+      kMaxResponseSizeKb);
+}
+
+base::TimeDelta ProtobufHttpRequest::GetRequestTimeoutDuration() const {
+  return timeout_duration_;
+}
+
 void ProtobufHttpRequest::OnResponse(
-    const ProtobufHttpStatus& status,
     std::unique_ptr<std::string> response_body) {
+  ProtobufHttpStatus status = GetUrlLoaderStatus();
   std::move(response_callback_)
       .Run(status.ok() ? ParseResponse(std::move(response_body)) : status);
+  std::move(invalidator_).Run();
 }
 
 ProtobufHttpStatus ProtobufHttpRequest::ParseResponse(

remoting/base/protobuf_http_request.h

@@ -5,35 +5,34 @@
 #ifndef REMOTING_BASE_PROTOBUF_HTTP_REQUEST_H_
 #define REMOTING_BASE_PROTOBUF_HTTP_REQUEST_H_
 
-#include <memory>
-#include <string>
-
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/time/time.h"
-#include "net/traffic_annotation/network_traffic_annotation.h"
-#include "remoting/base/protobuf_http_status.h"
-#include "third_party/protobuf/src/google/protobuf/message_lite.h"
+#include "remoting/base/protobuf_http_request_base.h"
+
+namespace google {
+namespace protobuf {
+class MessageLite;
+}  // namespace protobuf
+}  // namespace google
 
 namespace remoting {
 
-// A simple unary request. Caller needs to set all public members and call
-// SetResponseCallback() before passing it to ProtobufHttpClient.
-struct ProtobufHttpRequest final {
+// A simple unary request.
+class ProtobufHttpRequest final : public ProtobufHttpRequestBase {
+ public:
   template <typename ResponseType>
   using ResponseCallback =
       base::OnceCallback<void(const ProtobufHttpStatus& status,
                               std::unique_ptr<ResponseType> response)>;
 
   explicit ProtobufHttpRequest(
-      const net::NetworkTrafficAnnotationTag& traffic_annotation);
-  ~ProtobufHttpRequest();
+      std::unique_ptr<ProtobufHttpRequestConfig> config);
+  ~ProtobufHttpRequest() override;
 
-  const net::NetworkTrafficAnnotationTag traffic_annotation;
-  std::unique_ptr<google::protobuf::MessageLite> request_message;
-  std::string path;
-  bool authenticated = true;
-  base::TimeDelta timeout_duration = base::TimeDelta::FromSeconds(30);
+  // Sets the amount of time to wait before giving up on a given network request
+  // and considering it an error. The default value is 30s. Set it to zero to
+  // disable timeout.
+  void SetTimeoutDuration(base::TimeDelta timeout_duration);
 
   // Sets the response callback. |ResponseType| needs to be a protobuf message
   // type.
@@ -54,15 +53,19 @@ struct ProtobufHttpRequest final {
   }
 
  private:
-  friend class ProtobufHttpClient;
+  // ProtobufHttpRequestBase implementations.
+  void OnAuthFailed(const ProtobufHttpStatus& status) override;
+  void StartRequestInternal(
+      network::mojom::URLLoaderFactory* loader_factory) override;
+  base::TimeDelta GetRequestTimeoutDuration() const override;
 
-  // To be called by ProtobufHttpClient.
-  void OnResponse(const ProtobufHttpStatus& status,
-                  std::unique_ptr<std::string> response_body);
+  void OnResponse(std::unique_ptr<std::string> response_body);
 
   // Parses |response_body| and writes it to |response_message_|.
   ProtobufHttpStatus ParseResponse(std::unique_ptr<std::string> response_body);
 
+  base::TimeDelta timeout_duration_ = base::TimeDelta::FromSeconds(30);
+
   // This is owned by |response_callback_|.
   google::protobuf::MessageLite* response_message_;
   base::OnceCallback<void(const ProtobufHttpStatus&)> response_callback_;

remoting/base/protobuf_http_request_base.cc

+// Copyright 2020 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 "remoting/base/protobuf_http_request_base.h"
+
+#include "net/base/net_errors.h"
+#include "remoting/base/protobuf_http_request_config.h"
+#include "services/network/public/cpp/simple_url_loader.h"
+
+namespace remoting {
+
+ProtobufHttpRequestBase::ProtobufHttpRequestBase(
+    std::unique_ptr<ProtobufHttpRequestConfig> config)
+    : config_(std::move(config)) {
+  config_->Validate();
+}
+
+ProtobufHttpRequestBase::~ProtobufHttpRequestBase() {
+#if DCHECK_IS_ON()
+  DCHECK(request_deadline_.is_null() ||
+         request_deadline_ >= base::TimeTicks::Now())
+      << "The request must have been deleted before the deadline.";
+#endif  // DCHECK_IS_ON()
+}
+
+ProtobufHttpStatus ProtobufHttpRequestBase::GetUrlLoaderStatus() const {
+  net::Error net_error = static_cast<net::Error>(url_loader_->NetError());
+  if (net_error == net::Error::ERR_HTTP_RESPONSE_CODE_FAILURE &&
+      (!url_loader_->ResponseInfo() || !url_loader_->ResponseInfo()->headers)) {
+    LOG(ERROR) << "Can't find response header.";
+    net_error = net::Error::ERR_INVALID_RESPONSE;
+  }
+  return (net_error == net::Error::ERR_HTTP_RESPONSE_CODE_FAILURE ||
+          net_error == net::Error::OK)
+             ? ProtobufHttpStatus(static_cast<net::HttpStatusCode>(
+                   url_loader_->ResponseInfo()->headers->response_code()))
+             : ProtobufHttpStatus(net_error);
+}
+
+void ProtobufHttpRequestBase::StartRequest(
+    network::mojom::URLLoaderFactory* loader_factory,
+    std::unique_ptr<network::SimpleURLLoader> url_loader,
+    base::OnceClosure invalidator) {
+  DCHECK(!url_loader_);
+  DCHECK(!invalidator_);
+
+  url_loader_ = std::move(url_loader);
+  invalidator_ = std::move(invalidator);
+  StartRequestInternal(loader_factory);
+
+#if DCHECK_IS_ON()
+  base::TimeDelta timeout_duration = GetRequestTimeoutDuration();
+  if (!timeout_duration.is_zero()) {
+    // Add a 500ms fuzz to account for task dispatching delay and other stuff.
+    request_deadline_ = base::TimeTicks::Now() + timeout_duration +
+                        base::TimeDelta::FromMilliseconds(500);
+  }
+#endif  // DCHECK_IS_ON()
+}
+
+}  // namespace remoting

remoting/base/protobuf_http_request_base.h

+// Copyright 2020 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 REMOTING_BASE_PROTOBUF_HTTP_REQUEST_BASE_H_
+#define REMOTING_BASE_PROTOBUF_HTTP_REQUEST_BASE_H_
+
+#include <memory>
+#include <string>
+
+#include "base/callback.h"
+#include "base/dcheck_is_on.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "remoting/base/protobuf_http_status.h"
+
+namespace network {
+
+namespace mojom {
+class URLLoaderFactory;
+}  // namespace mojom
+
+class SimpleURLLoader;
+
+}  // namespace network
+
+namespace remoting {
+
+class ProtobufHttpClient;
+
+struct ProtobufHttpRequestConfig;
+
+// Base request class for unary and server streaming requests.
+class ProtobufHttpRequestBase {
+ public:
+  explicit ProtobufHttpRequestBase(
+      std::unique_ptr<ProtobufHttpRequestConfig> config);
+  virtual ~ProtobufHttpRequestBase();
+
+  const ProtobufHttpRequestConfig& config() const { return *config_; }
+
+ protected:
+  virtual void OnAuthFailed(const ProtobufHttpStatus& status) = 0;
+  virtual void StartRequestInternal(
+      network::mojom::URLLoaderFactory* loader_factory) = 0;
+
+  // Returns a deadline for when the request has to be finished. Returns zero
+  // if the request doesn't timeout. This is generally only useful for unary
+  // requests.
+  virtual base::TimeDelta GetRequestTimeoutDuration() const = 0;
+
+  // Returns the http status from |url_loader_|. Only useful when |url_loader_|
+  // informs that the request has been completed.
+  ProtobufHttpStatus GetUrlLoaderStatus() const;
+
+  std::unique_ptr<network::SimpleURLLoader> url_loader_;
+
+  // Subclass should run this closure whenever its lifetime ends, e.g. response
+  // is received or stream is closed. This will delete |this| from the parent
+  // ProtobufHttpClient.
+  base::OnceClosure invalidator_;
+
+ private:
+  friend class ProtobufHttpClient;
+
+  // Called by ProtobufHttpClient.
+  void StartRequest(network::mojom::URLLoaderFactory* loader_factory,
+                    std::unique_ptr<network::SimpleURLLoader> url_loader,
+                    base::OnceClosure invalidator);
+
+  std::unique_ptr<ProtobufHttpRequestConfig> config_;
+
+#if DCHECK_IS_ON()
+  base::TimeTicks request_deadline_;
+#endif  // DCHECK_IS_ON()
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_PROTOBUF_HTTP_REQUEST_BASE_H_

remoting/base/protobuf_http_request_config.cc

+// Copyright 2020 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 "remoting/base/protobuf_http_request_config.h"
+
+#include "third_party/protobuf/src/google/protobuf/message_lite.h"
+
+namespace remoting {
+
+ProtobufHttpRequestConfig::ProtobufHttpRequestConfig(
+    const net::NetworkTrafficAnnotationTag& traffic_annotation)
+    : traffic_annotation(traffic_annotation) {}
+
+ProtobufHttpRequestConfig::~ProtobufHttpRequestConfig() = default;
+
+void ProtobufHttpRequestConfig::Validate() const {
+  DCHECK(request_message);
+  DCHECK(!path.empty());
+}
+
+}  // namespace remoting

remoting/base/protobuf_http_request_config.h

+// Copyright 2020 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 REMOTING_BASE_PROTOBUF_HTTP_REQUEST_CONFIG_H_
+#define REMOTING_BASE_PROTOBUF_HTTP_REQUEST_CONFIG_H_
+
+#include <memory>
+#include <string>
+
+#include "net/traffic_annotation/network_traffic_annotation.h"
+
+namespace google {
+namespace protobuf {
+class MessageLite;
+}  // namespace protobuf
+}  // namespace google
+
+namespace remoting {
+
+// Common configurations for unary and stream protobuf http requests. Caller
+// needs to set all fields in this struct.
+struct ProtobufHttpRequestConfig {
+  explicit ProtobufHttpRequestConfig(
+      const net::NetworkTrafficAnnotationTag& traffic_annotation);
+  ~ProtobufHttpRequestConfig();
+
+  // Runs DCHECK's on the fields to make sure all fields have been set up.
+  void Validate() const;
+
+  const net::NetworkTrafficAnnotationTag traffic_annotation;
+  std::unique_ptr<google::protobuf::MessageLite> request_message;
+  std::string path;
+  bool authenticated = true;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_PROTOBUF_HTTP_REQUEST_CONFIG_H_

remoting/base/protobuf_http_stream_request.cc

+// Copyright 2020 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 "remoting/base/protobuf_http_stream_request.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "remoting/base/protobuf_http_client.h"
+#include "remoting/base/protobuf_http_request_config.h"
+#include "remoting/base/protobuf_http_status.h"
+#include "remoting/base/protobuf_http_stream_parser.h"
+#include "services/network/public/cpp/simple_url_loader.h"
+#include "third_party/protobuf/src/google/protobuf/message_lite.h"
+
+namespace remoting {
+
+ProtobufHttpStreamRequest::ProtobufHttpStreamRequest(
+    std::unique_ptr<ProtobufHttpRequestConfig> config)
+    : ProtobufHttpRequestBase(std::move(config)) {}
+
+ProtobufHttpStreamRequest::~ProtobufHttpStreamRequest() = default;
+
+void ProtobufHttpStreamRequest::SetStreamReadyCallback(
+    base::OnceClosure callback) {
+  stream_ready_callback_ = std::move(callback);
+}
+
+void ProtobufHttpStreamRequest::SetStreamClosedCallback(
+    StreamClosedCallback callback) {
+  stream_closed_callback_ = std::move(callback);
+}
+
+void ProtobufHttpStreamRequest::OnMessage(const std::string& message) {
+  std::unique_ptr<google::protobuf::MessageLite> protobuf_message(
+      default_message_->New());
+  if (protobuf_message->ParseFromString(message)) {
+    message_callback_.Run(std::move(protobuf_message));
+  } else {
+    LOG(ERROR) << "Failed to parse a stream message.";
+  }
+}
+
+void ProtobufHttpStreamRequest::OnStreamClosed(
+    const ProtobufHttpStatus& status) {
+  DCHECK(stream_closed_callback_);
+  DCHECK(invalidator_);
+
+  std::move(stream_closed_callback_).Run(status);
+  std::move(invalidator_).Run();
+}
+
+void ProtobufHttpStreamRequest::OnAuthFailed(const ProtobufHttpStatus& status) {
+  OnStreamClosed(status);
+}
+
+void ProtobufHttpStreamRequest::StartRequestInternal(
+    network::mojom::URLLoaderFactory* loader_factory) {
+  DCHECK(default_message_);
+  DCHECK(stream_ready_callback_);
+  DCHECK(stream_closed_callback_);
+  DCHECK(message_callback_);
+
+  // Safe to use unretained, as callbacks won't be called after |stream_parser_|
+  // is deleted.
+  stream_parser_ = std::make_unique<ProtobufHttpStreamParser>(
+      base::BindRepeating(&ProtobufHttpStreamRequest::OnMessage,
+                          base::Unretained(this)),
+      base::BindRepeating(&ProtobufHttpStreamRequest::OnStreamClosed,
+                          base::Unretained(this)));
+  url_loader_->DownloadAsStream(loader_factory, this);
+}
+
+base::TimeDelta ProtobufHttpStreamRequest::GetRequestTimeoutDuration() const {
+  return base::TimeDelta();
+}
+
+void ProtobufHttpStreamRequest::OnDataReceived(base::StringPiece string_piece,
+                                               base::OnceClosure resume) {
+  if (stream_ready_callback_) {
+    std::move(stream_ready_callback_).Run();
+  }
+
+  DCHECK(stream_parser_);
+  stream_parser_->Append(string_piece);
+  std::move(resume).Run();
+}
+
+void ProtobufHttpStreamRequest::OnComplete(bool success) {
+  OnStreamClosed(success ? ProtobufHttpStatus::OK : GetUrlLoaderStatus());
+}
+
+void ProtobufHttpStreamRequest::OnRetry(base::OnceClosure start_retry) {
+  NOTIMPLEMENTED();
+}
+
+}  // namespace remoting

remoting/base/protobuf_http_stream_request.h

+// Copyright 2020 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 REMOTING_BASE_PROTOBUF_HTTP_STREAM_REQUEST_H_
+#define REMOTING_BASE_PROTOBUF_HTTP_STREAM_REQUEST_H_
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "remoting/base/protobuf_http_request_base.h"
+#include "services/network/public/cpp/simple_url_loader_stream_consumer.h"
+
+namespace google {
+namespace protobuf {
+class MessageLite;
+}  // namespace protobuf
+}  // namespace google
+
+namespace remoting {
+
+class ProtobufHttpClient;
+class ProtobufHttpStatus;
+class ProtobufHttpStreamParser;
+
+// A server streaming request.
+class ProtobufHttpStreamRequest final
+    : public ProtobufHttpRequestBase,
+      public network::SimpleURLLoaderStreamConsumer {
+ public:
+  template <typename MessageType>
+  using MessageCallback =
+      base::RepeatingCallback<void(std::unique_ptr<MessageType> message)>;
+  using StreamClosedCallback =
+      base::OnceCallback<void(const ProtobufHttpStatus& status)>;
+
+  explicit ProtobufHttpStreamRequest(
+      std::unique_ptr<ProtobufHttpRequestConfig> config);
+  ~ProtobufHttpStreamRequest() override;
+
+  // Sets a callback that gets called when the stream is ready to receive data.
+  void SetStreamReadyCallback(base::OnceClosure callback);
+
+  // Sets a callback that gets called when the stream is closed.
+  void SetStreamClosedCallback(StreamClosedCallback callback);
+
+  // Sets the callback to be called every time a new message is received.
+  // |MessageType| needs to be a protobuf message type.
+  template <typename MessageType>
+  void SetMessageCallback(const MessageCallback<MessageType>& callback) {
+    default_message_ = &MessageType::default_instance();
+    message_callback_ = base::BindRepeating(
+        [](MessageCallback<MessageType> callback,
+           std::unique_ptr<google::protobuf::MessageLite> generic_message) {
+          std::move(callback).Run(std::unique_ptr<MessageType>(
+              static_cast<MessageType*>(generic_message.release())));
+        },
+        callback);
+  }
+
+  // TODO(yuweih): Consider adding an option to set timeout for
+  // |stream_ready_callback_|.
+
+ private:
+  friend class ProtobufHttpClient;
+
+  // ProtobufHttpStreamParser callbacks.
+  void OnMessage(const std::string& message);
+  void OnStreamClosed(const ProtobufHttpStatus& status);
+
+  // ProtobufHttpRequestBase implementations.
+  void OnAuthFailed(const ProtobufHttpStatus& status) override;
+  void StartRequestInternal(
+      network::mojom::URLLoaderFactory* loader_factory) override;
+  base::TimeDelta GetRequestTimeoutDuration() const override;
+
+  // network::SimpleURLLoaderStreamConsumer implementations.
+  void OnDataReceived(base::StringPiece string_piece,
+                      base::OnceClosure resume) override;
+  void OnComplete(bool success) override;
+  void OnRetry(base::OnceClosure start_retry) override;
+
+  // Used to create new response message instances.
+  const google::protobuf::MessageLite* default_message_;
+
+  std::unique_ptr<ProtobufHttpStreamParser> stream_parser_;
+
+  base::OnceClosure stream_ready_callback_;
+  StreamClosedCallback stream_closed_callback_;
+  base::RepeatingCallback<void(std::unique_ptr<google::protobuf::MessageLite>)>
+      message_callback_;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_PROTOBUF_HTTP_STREAM_REQUEST_H_