[CrOS PhoneHub] Create chromeos::secure_channel::NearbyConnectionBroker

This class creates an out-of-band Nearby connection using a pre-sycned
Bluetooth address. It will be used by the SecureChannel service to
implement connections for Phone Hub.

Bug: 1106937
Change-Id: I5dec7c8edc58b1188e423f1368d47727cd48eb1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2499361
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: James Vecore <vecore@google.com>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824997}

chrome/browser/chromeos/BUILD.gn

@@ -2601,6 +2601,10 @@ source_set("chromeos") {
     "scanning/zeroconf_scanner_detector_utils.h",
     "scheduler_configuration_manager.cc",
     "scheduler_configuration_manager.h",
+    "secure_channel/nearby_connection_broker.cc",
+    "secure_channel/nearby_connection_broker.h",
+    "secure_channel/nearby_connection_broker_impl.cc",
+    "secure_channel/nearby_connection_broker_impl.h",
     "secure_channel/nearby_endpoint_finder.cc",
     "secure_channel/nearby_endpoint_finder.h",
     "secure_channel/nearby_endpoint_finder_impl.cc",
@@ -3175,6 +3179,8 @@ static_library("test_support") {
     "printing/printing_stubs.h",
     "scoped_set_running_on_chromeos_for_testing.cc",
     "scoped_set_running_on_chromeos_for_testing.h",
+    "secure_channel/fake_nearby_connection_broker.cc",
+    "secure_channel/fake_nearby_connection_broker.h",
     "secure_channel/fake_nearby_endpoint_finder.cc",
     "secure_channel/fake_nearby_endpoint_finder.h",
     "settings/scoped_testing_cros_settings.cc",
@@ -3770,6 +3776,7 @@ source_set("unit_tests") {
     "scanning/scanning_type_converters_unittest.cc",
     "scanning/zeroconf_scanner_detector_unittest.cc",
     "scheduler_configuration_manager_unittest.cc",
+    "secure_channel/nearby_connection_broker_impl_unittest.cc",
     "secure_channel/nearby_endpoint_finder_impl_unittest.cc",
     "session_length_limiter_unittest.cc",
     "settings/cros_settings_unittest.cc",

chrome/browser/chromeos/secure_channel/fake_nearby_connection_broker.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 "chrome/browser/chromeos/secure_channel/fake_nearby_connection_broker.h"
+
+namespace chromeos {
+namespace secure_channel {
+
+FakeNearbyConnectionBroker::FakeNearbyConnectionBroker(
+    const std::vector<uint8_t>& bluetooth_public_address,
+    mojo::PendingReceiver<mojom::NearbyMessageSender> message_sender_receiver,
+    mojo::PendingRemote<mojom::NearbyMessageReceiver> message_receiver_remote,
+    base::OnceClosure on_connected_callback,
+    base::OnceClosure on_disconnected_callback)
+    : NearbyConnectionBroker(bluetooth_public_address,
+                             std::move(message_sender_receiver),
+                             std::move(message_receiver_remote),
+                             std::move(on_connected_callback),
+                             std::move(on_disconnected_callback)) {}
+
+FakeNearbyConnectionBroker::~FakeNearbyConnectionBroker() = default;
+
+void FakeNearbyConnectionBroker::SendMessage(const std::string& message,
+                                             SendMessageCallback callback) {
+  sent_messages_.push_back(message);
+  std::move(callback).Run(should_send_message_succeed_);
+}
+
+}  // namespace secure_channel
+}  // namespace chromeos

chrome/browser/chromeos/secure_channel/fake_nearby_connection_broker.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 CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_FAKE_NEARBY_CONNECTION_BROKER_H_
+#define CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_FAKE_NEARBY_CONNECTION_BROKER_H_
+
+#include "chrome/browser/chromeos/secure_channel/nearby_connection_broker.h"
+
+namespace chromeos {
+namespace secure_channel {
+
+class FakeNearbyConnectionBroker : public NearbyConnectionBroker {
+ public:
+  FakeNearbyConnectionBroker(
+      const std::vector<uint8_t>& bluetooth_public_address,
+      mojo::PendingReceiver<mojom::NearbyMessageSender> message_sender_receiver,
+      mojo::PendingRemote<mojom::NearbyMessageReceiver> message_receiver_remote,
+      base::OnceClosure on_connected_callback,
+      base::OnceClosure on_disconnected_callback);
+  ~FakeNearbyConnectionBroker() override;
+
+  using NearbyConnectionBroker::bluetooth_public_address;
+  using NearbyConnectionBroker::Disconnect;
+  using NearbyConnectionBroker::NotifyConnected;
+  using NearbyConnectionBroker::NotifyMessageReceived;
+
+  void set_should_send_message_succeed(bool should_send_message_succeed) {
+    should_send_message_succeed_ = should_send_message_succeed;
+  }
+
+  const std::vector<std::string>& sent_messages() const {
+    return sent_messages_;
+  }
+
+ private:
+  // mojom::NearbyMessageSender:
+  void SendMessage(const std::string& message,
+                   SendMessageCallback callback) override;
+
+  std::vector<std::string> sent_messages_;
+  bool should_send_message_succeed_ = true;
+};
+
+}  // namespace secure_channel
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_FAKE_NEARBY_CONNECTION_BROKER_H_

chrome/browser/chromeos/secure_channel/nearby_connection_broker.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 "chrome/browser/chromeos/secure_channel/nearby_connection_broker.h"
+
+#include "base/bind.h"
+#include "base/check.h"
+
+namespace chromeos {
+namespace secure_channel {
+
+NearbyConnectionBroker::NearbyConnectionBroker(
+    const std::vector<uint8_t>& bluetooth_public_address,
+    mojo::PendingReceiver<mojom::NearbyMessageSender> message_sender_receiver,
+    mojo::PendingRemote<mojom::NearbyMessageReceiver> message_receiver_remote,
+    base::OnceClosure on_connected_callback,
+    base::OnceClosure on_disconnected_callback)
+    : bluetooth_public_address_(bluetooth_public_address),
+      message_sender_receiver_(this, std::move(message_sender_receiver)),
+      message_receiver_remote_(std::move(message_receiver_remote)),
+      on_connected_callback_(std::move(on_connected_callback)),
+      on_disconnected_callback_(std::move(on_disconnected_callback)) {
+  message_sender_receiver_.set_disconnect_handler(base::BindOnce(
+      &NearbyConnectionBroker::Disconnect, base::Unretained(this)));
+  message_receiver_remote_.set_disconnect_handler(base::BindOnce(
+      &NearbyConnectionBroker::Disconnect, base::Unretained(this)));
+}
+
+NearbyConnectionBroker::~NearbyConnectionBroker() = default;
+
+void NearbyConnectionBroker::Disconnect() {
+  message_sender_receiver_.reset();
+  message_receiver_remote_.reset();
+
+  if (on_disconnected_callback_)
+    std::move(on_disconnected_callback_).Run();
+}
+
+void NearbyConnectionBroker::NotifyConnected() {
+  DCHECK(on_connected_callback_);
+  std::move(on_connected_callback_).Run();
+}
+
+void NearbyConnectionBroker::NotifyMessageReceived(
+    const std::string& received_message) {
+  message_receiver_remote_->OnMessageReceived(received_message);
+}
+
+}  // namespace secure_channel
+}  // namespace chromeos

chrome/browser/chromeos/secure_channel/nearby_connection_broker.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 CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_H_
+#define CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "chromeos/services/secure_channel/public/mojom/nearby_connector.mojom.h"
+#include "mojo/public/cpp/bindings/pending_receiver.h"
+#include "mojo/public/cpp/bindings/pending_remote.h"
+#include "mojo/public/cpp/bindings/receiver.h"
+#include "mojo/public/cpp/bindings/remote.h"
+
+namespace chromeos {
+namespace secure_channel {
+
+// Attempts to create a Nearby Connection to a remote device and exchange
+// messages on behalf of the SecureChannel service. Implements the
+// mojom::NearbyMessageSender interface so that SecureChannel can send messages
+// to Nearby Connections, and uses the mojom::NearbyMessageReceiver interface to
+// relay messages received from Nearby Connections back to SecureChannel.
+//
+// An instance of this class is only meant to be used for one connection
+// request to a single device. To make a new request, create a new object.
+class NearbyConnectionBroker : public mojom::NearbyMessageSender {
+ public:
+  ~NearbyConnectionBroker() override;
+
+ protected:
+  NearbyConnectionBroker(
+      const std::vector<uint8_t>& bluetooth_public_address,
+      mojo::PendingReceiver<mojom::NearbyMessageSender> message_sender_receiver,
+      mojo::PendingRemote<mojom::NearbyMessageReceiver> message_receiver_remote,
+      base::OnceClosure on_connected_callback,
+      base::OnceClosure on_disconnected_callback);
+
+  const std::vector<uint8_t>& bluetooth_public_address() const {
+    return bluetooth_public_address_;
+  }
+
+  void Disconnect();
+  void NotifyConnected();
+  void NotifyMessageReceived(const std::string& received_message);
+
+ private:
+  std::vector<uint8_t> bluetooth_public_address_;
+  mojo::Receiver<mojom::NearbyMessageSender> message_sender_receiver_;
+  mojo::Remote<mojom::NearbyMessageReceiver> message_receiver_remote_;
+  base::OnceClosure on_connected_callback_;
+  base::OnceClosure on_disconnected_callback_;
+};
+
+}  // namespace secure_channel
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_H_

chrome/browser/chromeos/secure_channel/nearby_connection_broker_impl.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 CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_IMPL_H_
+#define CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_IMPL_H_
+
+#include <memory>
+#include <ostream>
+
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/chromeos/secure_channel/nearby_connection_broker.h"
+#include "chromeos/services/nearby/public/mojom/nearby_connections.mojom.h"
+#include "mojo/public/cpp/bindings/shared_remote.h"
+
+namespace chromeos {
+namespace secure_channel {
+
+class NearbyEndpointFinder;
+
+// NearbyConnectionBroker implementation which utilizes NearbyEndpointFinder to
+// find an endpoint, then uses Nearby Connections to create and maintain a
+// connection. The overall process consists of:
+//   (1) Finding an endpoint via NearbyEndpointFinder.
+//   (2) Requesting a connection using that endpoint.
+//   (3) Accepting a connection.
+//   (4) Exchanging messages over the connection.
+//
+// Deleting an instance of this class tears down any active connection and
+// performs cleanup if necessary.
+//
+// TODO(khorimoto): Add the ability to upgrade bandwidth to WebRTC and to
+// receive payloads.
+class NearbyConnectionBrokerImpl
+    : public NearbyConnectionBroker,
+      public location::nearby::connections::mojom::ConnectionLifecycleListener,
+      public location::nearby::connections::mojom::PayloadListener {
+ public:
+  class Factory {
+   public:
+    static std::unique_ptr<NearbyConnectionBroker> Create(
+        const std::vector<uint8_t>& bluetooth_public_address,
+        NearbyEndpointFinder* endpoint_finder,
+        mojo::PendingReceiver<mojom::NearbyMessageSender>
+            message_sender_receiver,
+        mojo::PendingRemote<mojom::NearbyMessageReceiver>
+            message_receiver_remote,
+        const mojo::SharedRemote<
+            location::nearby::connections::mojom::NearbyConnections>&
+            nearby_connections,
+        base::OnceClosure on_connected_callback,
+        base::OnceClosure on_disconnected_callback);
+    static void SetFactoryForTesting(Factory* test_factory);
+
+    virtual ~Factory() = default;
+
+   protected:
+    virtual std::unique_ptr<NearbyConnectionBroker> CreateInstance(
+        const std::vector<uint8_t>& bluetooth_public_address,
+        NearbyEndpointFinder* endpoint_finder,
+        mojo::PendingReceiver<mojom::NearbyMessageSender>
+            message_sender_receiver,
+        mojo::PendingRemote<mojom::NearbyMessageReceiver>
+            message_receiver_remote,
+        const mojo::SharedRemote<
+            location::nearby::connections::mojom::NearbyConnections>&
+            nearby_connections,
+        base::OnceClosure on_connected_callback,
+        base::OnceClosure on_disconnected_callback) = 0;
+  };
+
+  ~NearbyConnectionBrokerImpl() override;
+
+ private:
+  enum class ConnectionStatus {
+    kUninitialized,
+    kDiscoveringEndpoint,
+    kRequestingConnection,
+    kWaitingForConnectionInitiation,
+    kAcceptingConnection,
+    kWaitingForConnectionToBeAcceptedByRemoteDevice,
+    kConnected,
+    kDisconnected,
+  };
+  friend std::ostream& operator<<(
+      std::ostream& stream,
+      NearbyConnectionBrokerImpl::ConnectionStatus status);
+
+  NearbyConnectionBrokerImpl(
+      const std::vector<uint8_t>& bluetooth_public_address,
+      NearbyEndpointFinder* endpoint_finder,
+      mojo::PendingReceiver<mojom::NearbyMessageSender> message_sender_receiver,
+      mojo::PendingRemote<mojom::NearbyMessageReceiver> message_receiver_remote,
+      const mojo::SharedRemote<
+          location::nearby::connections::mojom::NearbyConnections>&
+          nearby_connections,
+      base::OnceClosure on_connected_callback,
+      base::OnceClosure on_disconnected_callback);
+
+  void TransitionToStatus(ConnectionStatus connection_status);
+  void TransitionToDisconnected();
+
+  void OnEndpointDiscovered(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::DiscoveredEndpointInfoPtr info);
+  void OnDiscoveryFailure();
+
+  void OnRequestConnectionResult(
+      location::nearby::connections::mojom::Status status);
+  void OnAcceptConnectionResult(
+      location::nearby::connections::mojom::Status status);
+  void OnSendPayloadResult(SendMessageCallback callback,
+                           location::nearby::connections::mojom::Status status);
+
+  // mojom::NearbyMessageSender:
+  void SendMessage(const std::string& message,
+                   SendMessageCallback callback) override;
+
+  // location::nearby::connections::mojom::ConnectionLifecycleListener:
+  void OnConnectionInitiated(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::ConnectionInfoPtr info) override;
+  void OnConnectionAccepted(const std::string& endpoint_id) override;
+  void OnConnectionRejected(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::Status status) override;
+  void OnDisconnected(const std::string& endpoint_id) override;
+  void OnBandwidthChanged(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::Medium medium) override;
+
+  // location::nearby::connections::mojom::PayloadListener:
+  void OnPayloadReceived(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::PayloadPtr payload) override;
+  void OnPayloadTransferUpdate(
+      const std::string& endpoint_id,
+      location::nearby::connections::mojom::PayloadTransferUpdatePtr update)
+      override;
+
+  NearbyEndpointFinder* endpoint_finder_;
+  mojo::SharedRemote<location::nearby::connections::mojom::NearbyConnections>
+      nearby_connections_;
+
+  mojo::Receiver<
+      location::nearby::connections::mojom::ConnectionLifecycleListener>
+      connection_lifecycle_listener_receiver_{this};
+  mojo::Receiver<location::nearby::connections::mojom::PayloadListener>
+      payload_listener_receiver_{this};
+
+  ConnectionStatus connection_status_ = ConnectionStatus::kUninitialized;
+  int64_t next_sent_payload_id_ = 0L;
+
+  // Set once an endpoint is discovered.
+  std::string remote_endpoint_id_;
+
+  base::WeakPtrFactory<NearbyConnectionBrokerImpl> weak_ptr_factory_{this};
+};
+
+std::ostream& operator<<(std::ostream& stream,
+                         NearbyConnectionBrokerImpl::ConnectionStatus status);
+
+}  // namespace secure_channel
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SECURE_CHANNEL_NEARBY_CONNECTION_BROKER_IMPL_H_

chrome/browser/chromeos/secure_channel/nearby_connection_broker_impl_unittest.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 "chrome/browser/chromeos/secure_channel/nearby_connection_broker_impl.h"
+
+#include <memory>
+#include <vector>
+
+#include "base/run_loop.h"
+#include "base/test/bind_test_util.h"
+#include "base/test/task_environment.h"
+#include "chrome/browser/chromeos/secure_channel/fake_nearby_endpoint_finder.h"
+#include "chromeos/services/nearby/public/cpp/mock_nearby_connections.h"
+#include "chromeos/services/secure_channel/public/mojom/nearby_connector.mojom.h"
+#include "mojo/public/cpp/bindings/remote.h"
+#include "mojo/public/cpp/bindings/shared_remote.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromeos {
+namespace secure_channel {
+namespace {
+
+using location::nearby::connections::mojom::ConnectionInfo;
+using location::nearby::connections::mojom::ConnectionLifecycleListener;
+using location::nearby::connections::mojom::ConnectionOptionsPtr;
+using location::nearby::connections::mojom::DiscoveredEndpointInfo;
+using location::nearby::connections::mojom::EndpointDiscoveryListener;
+using location::nearby::connections::mojom::PayloadListener;
+using location::nearby::connections::mojom::PayloadPtr;
+using location::nearby::connections::mojom::Status;
+
+using testing::_;
+using testing::Invoke;
+
+const char kEndpointId[] = "endpointId";
+
+const std::vector<uint8_t>& GetBluetoothAddress() {
+  static const std::vector<uint8_t> address{0, 1, 2, 3, 4, 5};
+  return address;
+}
+
+const std::vector<uint8_t>& GetEndpointInfo() {
+  static const std::vector<uint8_t> info{6, 7, 8, 9, 10};
+  return info;
+}
+
+}  // namespace
+
+class NearbyConnectionBrokerImplTest : public testing::Test,
+                                       public mojom::NearbyMessageReceiver {
+ protected:
+  NearbyConnectionBrokerImplTest() = default;
+  ~NearbyConnectionBrokerImplTest() override = default;
+
+  // testing::Test:
+  void SetUp() override {
+    broker_ = NearbyConnectionBrokerImpl::Factory::Create(
+        GetBluetoothAddress(), &fake_endpoint_finder_,
+        message_sender_.BindNewPipeAndPassReceiver(),
+        message_receiver_.BindNewPipeAndPassRemote(),
+        mock_nearby_connections_.shared_remote(),
+        base::BindOnce(&NearbyConnectionBrokerImplTest::OnConnected,
+                       base::Unretained(this)),
+        base::BindOnce(&NearbyConnectionBrokerImplTest::OnDisconnected,
+                       base::Unretained(this)));
+    EXPECT_EQ(GetBluetoothAddress(),
+              fake_endpoint_finder_.remote_device_bluetooth_address());
+  }
+
+  void DiscoverEndpoint() {
+    base::RunLoop run_loop;
+    EXPECT_CALL(mock_nearby_connections_, RequestConnection(_, _, _, _, _, _))
+        .WillOnce(Invoke(
+            [&](const std::string& service_id,
+                const std::vector<uint8_t>& endpoint_info,
+                const std::string& endpoint_id, ConnectionOptionsPtr options,
+                mojo::PendingRemote<ConnectionLifecycleListener> listener,
+                NearbyConnectionsMojom::RequestConnectionCallback callback) {
+              request_connection_callback_ = std::move(callback);
+              connection_lifecycle_listener_.Bind(std::move(listener));
+              run_loop.Quit();
+            }));
+
+    fake_endpoint_finder_.NotifyEndpointFound(
+        kEndpointId,
+        DiscoveredEndpointInfo::New(GetEndpointInfo(), mojom::kServiceId));
+
+    run_loop.Run();
+  }
+
+  void FailDiscovery() {
+    base::RunLoop run_loop;
+    on_disconnected_closure_ = run_loop.QuitClosure();
+    fake_endpoint_finder_.NotifyEndpointDiscoveryFailure();
+    run_loop.Run();
+  }
+
+  void InvokeRequestConnectionCallback(bool success) {
+    if (!success) {
+      base::RunLoop run_loop;
+      on_disconnected_closure_ = run_loop.QuitClosure();
+      std::move(request_connection_callback_).Run(Status::kError);
+      run_loop.Run();
+      return;
+    }
+
+    std::move(request_connection_callback_).Run(Status::kSuccess);
+
+    // Ensure that callback result is received; cannot use external event
+    // because the success callback only updates internal state.
+    base::RunLoop().RunUntilIdle();
+  }
+
+  void NotifyConnectionInitiated() {
+    base::RunLoop run_loop;
+    EXPECT_CALL(mock_nearby_connections_, AcceptConnection(_, _, _, _))
+        .WillOnce(Invoke(
+            [&](const std::string& service_id, const std::string& endpoint_id,
+                mojo::PendingRemote<PayloadListener> listener,
+                NearbyConnectionsMojom::AcceptConnectionCallback callback) {
+              accept_connection_callback_ = std::move(callback);
+              payload_listener_listener_.Bind(std::move(listener));
+              run_loop.Quit();
+            }));
+
+    connection_lifecycle_listener_->OnConnectionInitiated(
+        kEndpointId, ConnectionInfo::New());
+
+    run_loop.Run();
+  }
+
+  void InvokeAcceptConnectionCallback(bool success) {
+    if (!success) {
+      base::RunLoop run_loop;
+      on_disconnected_closure_ = run_loop.QuitClosure();
+      std::move(accept_connection_callback_).Run(Status::kError);
+      run_loop.Run();
+      return;
+    }
+
+    std::move(accept_connection_callback_).Run(Status::kSuccess);
+
+    // Ensure that callback result is received; cannot use external event
+    // because the success callback only updates internal state.
+    base::RunLoop().RunUntilIdle();
+  }
+
+  void NotifyConnectionAccepted() {
+    base::RunLoop run_loop;
+    on_connected_closure_ = run_loop.QuitClosure();
+    connection_lifecycle_listener_->OnConnectionAccepted(kEndpointId);
+    run_loop.Run();
+  }
+
+  void SetUpFullConnection() {
+    DiscoverEndpoint();
+    InvokeRequestConnectionCallback(/*success=*/true);
+    NotifyConnectionInitiated();
+    InvokeAcceptConnectionCallback(/*success=*/true);
+    NotifyConnectionAccepted();
+  }
+
+  void SendMessage(const std::string& message, bool success) {
+    base::RunLoop send_message_run_loop;
+    base::RunLoop send_message_response_run_loop;
+
+    NearbyConnectionsMojom::SendPayloadCallback send_payload_callback;
+    std::string sent_message;
+    EXPECT_CALL(mock_nearby_connections_, SendPayload(_, _, _, _))
+        .WillOnce(
+            Invoke([&](const std::string& service_id,
+                       const std::vector<std::string>& endpoint_ids,
+                       PayloadPtr payload,
+                       NearbyConnectionsMojom::SendPayloadCallback callback) {
+              send_payload_callback = std::move(callback);
+
+              const std::vector<uint8_t>& payload_bytes =
+                  payload->content->get_bytes()->bytes;
+              sent_message =
+                  std::string(payload_bytes.begin(), payload_bytes.end());
+
+              send_message_run_loop.Quit();
+            }));
+
+    message_sender_->SendMessage(
+        message, base::BindLambdaForTesting([&](bool did_send_succeeed) {
+          EXPECT_EQ(success, did_send_succeeed);
+          send_message_response_run_loop.Quit();
+        }));
+    send_message_run_loop.Run();
+
+    EXPECT_EQ(message, sent_message);
+
+    if (success) {
+      std::move(send_payload_callback).Run(Status::kSuccess);
+      send_message_response_run_loop.Run();
+      return;
+    }
+
+    // Failure to send should disconnect the ongoing connection.
+    base::RunLoop disconnect_run_loop;
+    on_disconnected_closure_ = disconnect_run_loop.QuitClosure();
+    std::move(send_payload_callback).Run(Status::kError);
+    send_message_response_run_loop.Run();
+    disconnect_run_loop.Run();
+  }
+
+  // TODO(khormoto): Verify received messages once this functionality is
+  // implemented.
+  std::vector<std::string> received_messages_;
+
+ private:
+  // mojom::NearbyMessageReceiver:
+  void OnMessageReceived(const std::string& message) override {
+    received_messages_.push_back(message);
+  }
+
+  void OnConnected() { std::move(on_connected_closure_).Run(); }
+
+  void OnDisconnected() { std::move(on_disconnected_closure_).Run(); }
+
+  base::test::TaskEnvironment task_environment_;
+  nearby::MockNearbyConnections mock_nearby_connections_;
+  FakeNearbyEndpointFinder fake_endpoint_finder_;
+
+  mojo::Remote<mojom::NearbyMessageSender> message_sender_;
+  mojo::Receiver<mojom::NearbyMessageReceiver> message_receiver_{this};
+
+  std::unique_ptr<NearbyConnectionBroker> broker_;
+
+  base::OnceClosure on_connected_closure_;
+  base::OnceClosure on_disconnected_closure_;
+
+  NearbyConnectionsMojom::RequestConnectionCallback
+      request_connection_callback_;
+  NearbyConnectionsMojom::AcceptConnectionCallback accept_connection_callback_;
+
+  mojo::Remote<ConnectionLifecycleListener> connection_lifecycle_listener_;
+  mojo::Remote<PayloadListener> payload_listener_listener_;
+};
+
+// TODO(khorimoto): Add test for receiving incoming messages.
+TEST_F(NearbyConnectionBrokerImplTest, SendAndReceive) {
+  SetUpFullConnection();
+  SendMessage("test1", /*success=*/true);
+  SendMessage("test2", /*success=*/true);
+}
+
+TEST_F(NearbyConnectionBrokerImplTest, FailToSend) {
+  SetUpFullConnection();
+  SendMessage("test", /*success=*/false);
+}
+
+TEST_F(NearbyConnectionBrokerImplTest, FailDiscovery) {
+  FailDiscovery();
+}
+
+TEST_F(NearbyConnectionBrokerImplTest, FailRequestingConnection) {
+  DiscoverEndpoint();
+  InvokeRequestConnectionCallback(/*success=*/false);
+}
+
+TEST_F(NearbyConnectionBrokerImplTest, FailAcceptingConnection) {
+  DiscoverEndpoint();
+  InvokeRequestConnectionCallback(/*success=*/true);
+  NotifyConnectionInitiated();
+  InvokeAcceptConnectionCallback(/*success=*/false);
+}
+
+}  // namespace secure_channel
+}  // namespace chromeos

chromeos/services/secure_channel/public/mojom/nearby_connector.mojom

@@ -8,4 +8,15 @@ module chromeos.secure_channel.mojom;
 // with each connection request.
 const string kServiceId = "secure_channel";
 
-// TODO(khorimoto): Add SecureChannel interfaces for Nearby Connections.
+// Sends messages over a Nearby Connection.
\ No newline at end of file
+interface NearbyMessageSender {
+  // Sends |message|, returning whether the message was sent successfully.
+  SendMessage(string message) => (bool success);
+};
+
+// Receives messages over a Nearby connection.
+interface NearbyMessageReceiver {
+  // Called whenever a message is received over the connection.
+  OnMessageReceived(string message);
+};
+