1 files changed, 791 insertions, 0 deletions
diff --git a/third_party/libwebrtc/pc/peer_connection_histogram_unittest.cc b/third_party/libwebrtc/pc/peer_connection_histogram_unittest.cc
new file mode 100644
index 0000000000..656b022ebd
--- /dev/null
+++ b/third_party/libwebrtc/pc/peer_connection_histogram_unittest.cc
@@ -0,0 +1,791 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <memory>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/async_resolver_factory.h"
+#include "api/call/call_factory_interface.h"
+#include "api/jsep.h"
+#include "api/jsep_session_description.h"
+#include "api/peer_connection_interface.h"
+#include "api/rtc_error.h"
+#include "api/scoped_refptr.h"
+#include "api/task_queue/default_task_queue_factory.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "media/base/fake_media_engine.h"
+#include "media/base/media_engine.h"
+#include "p2p/base/mock_async_resolver.h"
+#include "p2p/base/port_allocator.h"
+#include "p2p/client/basic_port_allocator.h"
+#include "pc/peer_connection.h"
+#include "pc/peer_connection_factory.h"
+#include "pc/peer_connection_proxy.h"
+#include "pc/peer_connection_wrapper.h"
+#include "pc/sdp_utils.h"
+#include "pc/test/mock_peer_connection_observers.h"
+#include "pc/usage_pattern.h"
+#include "pc/webrtc_sdp.h"
+#include "rtc_base/arraysize.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/fake_mdns_responder.h"
+#include "rtc_base/fake_network.h"
+#include "rtc_base/gunit.h"
+#include "rtc_base/mdns_responder_interface.h"
+#include "rtc_base/socket_address.h"
+#include "rtc_base/thread.h"
+#include "rtc_base/virtual_socket_server.h"
+#include "system_wrappers/include/metrics.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+using RTCConfiguration = PeerConnectionInterface::RTCConfiguration;
+using RTCOfferAnswerOptions = PeerConnectionInterface::RTCOfferAnswerOptions;
+using ::testing::NiceMock;
+using ::testing::Values;
+
+static const char kUsagePatternMetric[] = "WebRTC.PeerConnection.UsagePattern";
+static constexpr int kDefaultTimeout = 10000;
+static const rtc::SocketAddress kLocalAddrs[2] = {
+    rtc::SocketAddress("1.1.1.1", 0), rtc::SocketAddress("2.2.2.2", 0)};
+static const rtc::SocketAddress kPrivateLocalAddress("10.1.1.1", 0);
+static const rtc::SocketAddress kPrivateIpv6LocalAddress("fd12:3456:789a:1::1",
+                                                         0);
+
+int MakeUsageFingerprint(std::set<UsageEvent> events) {
+  int signature = 0;
+  for (const auto it : events) {
+    signature |= static_cast<int>(it);
+  }
+  return signature;
+}
+
+class PeerConnectionFactoryForUsageHistogramTest
+    : public PeerConnectionFactory {
+ public:
+  PeerConnectionFactoryForUsageHistogramTest()
+      : PeerConnectionFactory([] {
+          PeerConnectionFactoryDependencies dependencies;
+          dependencies.network_thread = rtc::Thread::Current();
+          dependencies.worker_thread = rtc::Thread::Current();
+          dependencies.signaling_thread = rtc::Thread::Current();
+          dependencies.task_queue_factory = CreateDefaultTaskQueueFactory();
+          dependencies.media_engine =
+              std::make_unique<cricket::FakeMediaEngine>();
+          dependencies.call_factory = CreateCallFactory();
+          return dependencies;
+        }()) {}
+};
+
+class PeerConnectionWrapperForUsageHistogramTest;
+
+typedef PeerConnectionWrapperForUsageHistogramTest* RawWrapperPtr;
+
+class ObserverForUsageHistogramTest : public MockPeerConnectionObserver {
+ public:
+  void OnIceCandidate(const webrtc::IceCandidateInterface* candidate) override;
+
+  void OnInterestingUsage(int usage_pattern) override {
+    interesting_usage_detected_ = usage_pattern;
+  }
+
+  void PrepareToExchangeCandidates(RawWrapperPtr other) {
+    candidate_target_ = other;
+  }
+
+  bool HaveDataChannel() { return last_datachannel_ != nullptr; }
+
+  absl::optional<int> interesting_usage_detected() {
+    return interesting_usage_detected_;
+  }
+
+  void ClearInterestingUsageDetector() {
+    interesting_usage_detected_ = absl::optional<int>();
+  }
+
+  bool candidate_gathered() const { return candidate_gathered_; }
+
+ private:
+  absl::optional<int> interesting_usage_detected_;
+  bool candidate_gathered_ = false;
+  RawWrapperPtr candidate_target_;  // Note: Not thread-safe against deletions.
+};
+
+class PeerConnectionWrapperForUsageHistogramTest
+    : public PeerConnectionWrapper {
+ public:
+  using PeerConnectionWrapper::PeerConnectionWrapper;
+
+  PeerConnection* GetInternalPeerConnection() {
+    auto* pci =
+        static_cast<PeerConnectionProxyWithInternal<PeerConnectionInterface>*>(
+            pc());
+    return static_cast<PeerConnection*>(pci->internal());
+  }
+
+  // Override with different return type
+  ObserverForUsageHistogramTest* observer() {
+    return static_cast<ObserverForUsageHistogramTest*>(
+        PeerConnectionWrapper::observer());
+  }
+
+  void PrepareToExchangeCandidates(
+      PeerConnectionWrapperForUsageHistogramTest* other) {
+    observer()->PrepareToExchangeCandidates(other);
+    other->observer()->PrepareToExchangeCandidates(this);
+  }
+
+  bool IsConnected() {
+    return pc()->ice_connection_state() ==
+               PeerConnectionInterface::kIceConnectionConnected ||
+           pc()->ice_connection_state() ==
+               PeerConnectionInterface::kIceConnectionCompleted;
+  }
+
+  bool HaveDataChannel() {
+    return static_cast<ObserverForUsageHistogramTest*>(observer())
+        ->HaveDataChannel();
+  }
+  void BufferIceCandidate(const webrtc::IceCandidateInterface* candidate) {
+    std::string sdp;
+    EXPECT_TRUE(candidate->ToString(&sdp));
+    std::unique_ptr<webrtc::IceCandidateInterface> candidate_copy(
+        CreateIceCandidate(candidate->sdp_mid(), candidate->sdp_mline_index(),
+                           sdp, nullptr));
+    buffered_candidates_.push_back(std::move(candidate_copy));
+  }
+
+  void AddBufferedIceCandidates() {
+    for (const auto& candidate : buffered_candidates_) {
+      EXPECT_TRUE(pc()->AddIceCandidate(candidate.get()));
+    }
+    buffered_candidates_.clear();
+  }
+
+  // This method performs the following actions in sequence:
+  // 1. Exchange Offer and Answer.
+  // 2. Exchange ICE candidates after both caller and callee complete
+  // gathering.
+  // 3. Wait for ICE to connect.
+  //
+  // This guarantees a deterministic sequence of events and also rules out the
+  // occurrence of prflx candidates if the offer/answer signaling and the
+  // candidate trickling race in order. In case prflx candidates need to be
+  // simulated, see the approach used by tests below for that.
+  bool ConnectTo(PeerConnectionWrapperForUsageHistogramTest* callee) {
+    PrepareToExchangeCandidates(callee);
+    if (!ExchangeOfferAnswerWith(callee)) {
+      return false;
+    }
+    // Wait until the gathering completes before we signal the candidate.
+    WAIT(observer()->ice_gathering_complete_, kDefaultTimeout);
+    WAIT(callee->observer()->ice_gathering_complete_, kDefaultTimeout);
+    AddBufferedIceCandidates();
+    callee->AddBufferedIceCandidates();
+    WAIT(IsConnected(), kDefaultTimeout);
+    WAIT(callee->IsConnected(), kDefaultTimeout);
+    return IsConnected() && callee->IsConnected();
+  }
+
+  bool GenerateOfferAndCollectCandidates() {
+    auto offer = CreateOffer(RTCOfferAnswerOptions());
+    if (!offer) {
+      return false;
+    }
+    bool set_local_offer =
+        SetLocalDescription(CloneSessionDescription(offer.get()));
+    EXPECT_TRUE(set_local_offer);
+    if (!set_local_offer) {
+      return false;
+    }
+    EXPECT_TRUE_WAIT(observer()->ice_gathering_complete_, kDefaultTimeout);
+    return true;
+  }
+
+  webrtc::PeerConnectionInterface::IceGatheringState ice_gathering_state() {
+    return pc()->ice_gathering_state();
+  }
+
+ private:
+  // Candidates that have been sent but not yet configured
+  std::vector<std::unique_ptr<webrtc::IceCandidateInterface>>
+      buffered_candidates_;
+};
+
+// Buffers candidates until we add them via AddBufferedIceCandidates.
+void ObserverForUsageHistogramTest::OnIceCandidate(
+    const webrtc::IceCandidateInterface* candidate) {
+  // If target is not set, ignore. This happens in one-ended unit tests.
+  if (candidate_target_) {
+    this->candidate_target_->BufferIceCandidate(candidate);
+  }
+  candidate_gathered_ = true;
+}
+
+class PeerConnectionUsageHistogramTest : public ::testing::Test {
+ protected:
+  typedef std::unique_ptr<PeerConnectionWrapperForUsageHistogramTest>
+      WrapperPtr;
+
+  PeerConnectionUsageHistogramTest()
+      : vss_(new rtc::VirtualSocketServer()), main_(vss_.get()) {
+    webrtc::metrics::Reset();
+  }
+
+  WrapperPtr CreatePeerConnection() {
+    RTCConfiguration config;
+    config.sdp_semantics = webrtc::SdpSemantics::kUnifiedPlan;
+    return CreatePeerConnection(
+        config, PeerConnectionFactoryInterface::Options(), nullptr);
+  }
+
+  WrapperPtr CreatePeerConnection(const RTCConfiguration& config) {
+    return CreatePeerConnection(
+        config, PeerConnectionFactoryInterface::Options(), nullptr);
+  }
+
+  WrapperPtr CreatePeerConnectionWithMdns(const RTCConfiguration& config) {
+    auto resolver_factory =
+        std::make_unique<NiceMock<webrtc::MockAsyncResolverFactory>>();
+
+    webrtc::PeerConnectionDependencies deps(nullptr /* observer_in */);
+
+    auto fake_network = NewFakeNetwork();
+    fake_network->set_mdns_responder(
+        std::make_unique<webrtc::FakeMdnsResponder>(rtc::Thread::Current()));
+    fake_network->AddInterface(NextLocalAddress());
+
+    std::unique_ptr<cricket::BasicPortAllocator> port_allocator(
+        new cricket::BasicPortAllocator(
+            fake_network,
+            std::make_unique<rtc::BasicPacketSocketFactory>(vss_.get())));
+
+    deps.async_resolver_factory = std::move(resolver_factory);
+    deps.allocator = std::move(port_allocator);
+
+    return CreatePeerConnection(
+        config, PeerConnectionFactoryInterface::Options(), std::move(deps));
+  }
+
+  WrapperPtr CreatePeerConnectionWithImmediateReport() {
+    RTCConfiguration configuration;
+    configuration.sdp_semantics = webrtc::SdpSemantics::kUnifiedPlan;
+    configuration.report_usage_pattern_delay_ms = 0;
+    return CreatePeerConnection(
+        configuration, PeerConnectionFactoryInterface::Options(), nullptr);
+  }
+
+  WrapperPtr CreatePeerConnectionWithPrivateLocalAddresses() {
+    auto* fake_network = NewFakeNetwork();
+    fake_network->AddInterface(NextLocalAddress());
+    fake_network->AddInterface(kPrivateLocalAddress);
+
+    auto port_allocator = std::make_unique<cricket::BasicPortAllocator>(
+        fake_network,
+        std::make_unique<rtc::BasicPacketSocketFactory>(vss_.get()));
+    RTCConfiguration config;
+    config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+    return CreatePeerConnection(config,
+                                PeerConnectionFactoryInterface::Options(),
+                                std::move(port_allocator));
+  }
+
+  WrapperPtr CreatePeerConnectionWithPrivateIpv6LocalAddresses() {
+    auto* fake_network = NewFakeNetwork();
+    fake_network->AddInterface(NextLocalAddress());
+    fake_network->AddInterface(kPrivateIpv6LocalAddress);
+
+    auto port_allocator = std::make_unique<cricket::BasicPortAllocator>(
+        fake_network,
+        std::make_unique<rtc::BasicPacketSocketFactory>(vss_.get()));
+
+    RTCConfiguration config;
+    config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+    return CreatePeerConnection(config,
+                                PeerConnectionFactoryInterface::Options(),
+                                std::move(port_allocator));
+  }
+
+  WrapperPtr CreatePeerConnection(
+      const RTCConfiguration& config,
+      const PeerConnectionFactoryInterface::Options factory_options,
+      std::unique_ptr<cricket::PortAllocator> allocator) {
+    PeerConnectionDependencies deps(nullptr);
+    deps.allocator = std::move(allocator);
+
+    return CreatePeerConnection(config, factory_options, std::move(deps));
+  }
+
+  WrapperPtr CreatePeerConnection(
+      const RTCConfiguration& config,
+      const PeerConnectionFactoryInterface::Options factory_options,
+      PeerConnectionDependencies deps) {
+    auto pc_factory =
+        rtc::make_ref_counted<PeerConnectionFactoryForUsageHistogramTest>();
+    pc_factory->SetOptions(factory_options);
+
+    // If no allocator is provided, one will be created using a network manager
+    // that uses the host network. This doesn't work on all trybots.
+    if (!deps.allocator) {
+      auto fake_network = NewFakeNetwork();
+      fake_network->AddInterface(NextLocalAddress());
+      deps.allocator = std::make_unique<cricket::BasicPortAllocator>(
+          fake_network,
+          std::make_unique<rtc::BasicPacketSocketFactory>(vss_.get()));
+    }
+
+    auto observer = std::make_unique<ObserverForUsageHistogramTest>();
+    deps.observer = observer.get();
+
+    auto result =
+        pc_factory->CreatePeerConnectionOrError(config, std::move(deps));
+    if (!result.ok()) {
+      return nullptr;
+    }
+
+    observer->SetPeerConnectionInterface(result.value().get());
+    auto wrapper = std::make_unique<PeerConnectionWrapperForUsageHistogramTest>(
+        pc_factory, result.MoveValue(), std::move(observer));
+    return wrapper;
+  }
+
+  int ObservedFingerprint() {
+    // This works correctly only if there is only one sample value
+    // that has been counted.
+    // Returns -1 for "not found".
+    return webrtc::metrics::MinSample(kUsagePatternMetric);
+  }
+
+  // The PeerConnection's port allocator is tied to the PeerConnection's
+  // lifetime and expects the underlying NetworkManager to outlive it.  That
+  // prevents us from having the PeerConnectionWrapper own the fake network.
+  // Therefore, the test fixture will own all the fake networks even though
+  // tests should access the fake network through the PeerConnectionWrapper.
+  rtc::FakeNetworkManager* NewFakeNetwork() {
+    fake_networks_.emplace_back(std::make_unique<rtc::FakeNetworkManager>());
+    return fake_networks_.back().get();
+  }
+
+  rtc::SocketAddress NextLocalAddress() {
+    RTC_DCHECK(next_local_address_ < (int)arraysize(kLocalAddrs));
+    return kLocalAddrs[next_local_address_++];
+  }
+
+  std::vector<std::unique_ptr<rtc::FakeNetworkManager>> fake_networks_;
+  int next_local_address_ = 0;
+  std::unique_ptr<rtc::VirtualSocketServer> vss_;
+  rtc::AutoSocketServerThread main_;
+};
+
+TEST_F(PeerConnectionUsageHistogramTest, UsageFingerprintHistogramFromTimeout) {
+  auto pc = CreatePeerConnectionWithImmediateReport();
+
+  int expected_fingerprint = MakeUsageFingerprint({});
+  EXPECT_METRIC_EQ_WAIT(1, webrtc::metrics::NumSamples(kUsagePatternMetric),
+                        kDefaultTimeout);
+  EXPECT_METRIC_EQ(
+      1, webrtc::metrics::NumEvents(kUsagePatternMetric, expected_fingerprint));
+}
+
+#ifndef WEBRTC_ANDROID
+// These tests do not work on Android. Why is unclear.
+// https://bugs.webrtc.org/9461
+
+// Test getting the usage fingerprint for an audio/video connection.
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintAudioVideo) {
+  auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
+  caller->AddAudioTrack("audio");
+  caller->AddVideoTrack("video");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  caller->pc()->Close();
+  callee->pc()->Close();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::VIDEO_ADDED,
+       UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::ICE_STATE_CONNECTED, UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  // In this case, we may or may not have PRIVATE_CANDIDATE_COLLECTED,
+  // depending on the machine configuration.
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_TRUE(
+      webrtc::metrics::NumEvents(kUsagePatternMetric, expected_fingerprint) ==
+          2 ||
+      webrtc::metrics::NumEvents(
+          kUsagePatternMetric,
+          expected_fingerprint |
+              static_cast<int>(UsageEvent::PRIVATE_CANDIDATE_COLLECTED)) == 2);
+}
+
+// Test getting the usage fingerprint when the caller collects an mDNS
+// candidate.
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintWithMdnsCaller) {
+  RTCConfiguration config;
+  config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+
+  // Enable hostname candidates with mDNS names.
+  auto caller = CreatePeerConnectionWithMdns(config);
+  auto callee = CreatePeerConnection(config);
+
+  caller->AddAudioTrack("audio");
+  caller->AddVideoTrack("video");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  caller->pc()->Close();
+  callee->pc()->Close();
+
+  int expected_fingerprint_caller = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::VIDEO_ADDED,
+       UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::MDNS_CANDIDATE_COLLECTED,
+       UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+
+  // Without a resolver, the callee cannot resolve the received mDNS candidate
+  // but can still connect with the caller via a prflx candidate. As a result,
+  // the bit for the direct connection should not be logged.
+  int expected_fingerprint_callee = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::VIDEO_ADDED,
+       UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::REMOTE_MDNS_CANDIDATE_ADDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_caller));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_callee));
+}
+
+// Test getting the usage fingerprint when the callee collects an mDNS
+// candidate.
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintWithMdnsCallee) {
+  RTCConfiguration config;
+  config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+
+  // Enable hostname candidates with mDNS names.
+  auto caller = CreatePeerConnection(config);
+  auto callee = CreatePeerConnectionWithMdns(config);
+
+  caller->AddAudioTrack("audio");
+  caller->AddVideoTrack("video");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  caller->pc()->Close();
+  callee->pc()->Close();
+
+  // Similar to the test above, the caller connects with the callee via a prflx
+  // candidate.
+  int expected_fingerprint_caller = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::VIDEO_ADDED,
+       UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::REMOTE_MDNS_CANDIDATE_ADDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED, UsageEvent::CLOSE_CALLED});
+
+  int expected_fingerprint_callee = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::VIDEO_ADDED,
+       UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::MDNS_CANDIDATE_COLLECTED,
+       UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_caller));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_callee));
+}
+
+#ifdef WEBRTC_HAVE_SCTP
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintDataOnly) {
+  auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
+  caller->CreateDataChannel("foodata");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  ASSERT_TRUE_WAIT(callee->HaveDataChannel(), kDefaultTimeout);
+  caller->pc()->Close();
+  callee->pc()->Close();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::ICE_STATE_CONNECTED, UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_TRUE(
+      webrtc::metrics::NumEvents(kUsagePatternMetric, expected_fingerprint) ==
+          2 ||
+      webrtc::metrics::NumEvents(
+          kUsagePatternMetric,
+          expected_fingerprint |
+              static_cast<int>(UsageEvent::PRIVATE_CANDIDATE_COLLECTED)) == 2);
+}
+#endif  // WEBRTC_HAVE_SCTP
+#endif  // WEBRTC_ANDROID
+
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintStunTurn) {
+  RTCConfiguration configuration;
+  configuration.sdp_semantics = SdpSemantics::kUnifiedPlan;
+  PeerConnection::IceServer server;
+  server.urls = {"stun:dummy.stun.server"};
+  configuration.servers.push_back(server);
+  server.urls = {"turn:dummy.turn.server"};
+  server.username = "username";
+  server.password = "password";
+  configuration.servers.push_back(server);
+  auto caller = CreatePeerConnection(configuration);
+  ASSERT_TRUE(caller);
+  caller->pc()->Close();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::STUN_SERVER_ADDED, UsageEvent::TURN_SERVER_ADDED,
+       UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(
+      1, webrtc::metrics::NumEvents(kUsagePatternMetric, expected_fingerprint));
+}
+
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintStunTurnInReconfiguration) {
+  RTCConfiguration configuration;
+  configuration.sdp_semantics = SdpSemantics::kUnifiedPlan;
+  PeerConnection::IceServer server;
+  server.urls = {"stun:dummy.stun.server"};
+  configuration.servers.push_back(server);
+  server.urls = {"turn:dummy.turn.server"};
+  server.username = "username";
+  server.password = "password";
+  configuration.servers.push_back(server);
+  auto caller = CreatePeerConnection();
+  ASSERT_TRUE(caller);
+  ASSERT_TRUE(caller->pc()->SetConfiguration(configuration).ok());
+  caller->pc()->Close();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::STUN_SERVER_ADDED, UsageEvent::TURN_SERVER_ADDED,
+       UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(
+      1, webrtc::metrics::NumEvents(kUsagePatternMetric, expected_fingerprint));
+}
+
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintWithPrivateIPCaller) {
+  auto caller = CreatePeerConnectionWithPrivateLocalAddresses();
+  auto callee = CreatePeerConnection();
+  caller->AddAudioTrack("audio");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  caller->pc()->Close();
+  callee->pc()->Close();
+
+  int expected_fingerprint_caller = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::PRIVATE_CANDIDATE_COLLECTED,
+       UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+
+  int expected_fingerprint_callee = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::REMOTE_PRIVATE_CANDIDATE_ADDED,
+       UsageEvent::ICE_STATE_CONNECTED, UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_caller));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_callee));
+}
+
+TEST_F(PeerConnectionUsageHistogramTest, FingerprintWithPrivateIpv6Callee) {
+  auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnectionWithPrivateIpv6LocalAddresses();
+  caller->AddAudioTrack("audio");
+  ASSERT_TRUE(caller->ConnectTo(callee.get()));
+  caller->pc()->Close();
+  callee->pc()->Close();
+
+  int expected_fingerprint_caller = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::REMOTE_PRIVATE_CANDIDATE_ADDED,
+       UsageEvent::ICE_STATE_CONNECTED, UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::REMOTE_IPV6_CANDIDATE_ADDED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+
+  int expected_fingerprint_callee = MakeUsageFingerprint(
+      {UsageEvent::AUDIO_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::PRIVATE_CANDIDATE_COLLECTED,
+       UsageEvent::IPV6_CANDIDATE_COLLECTED,
+       UsageEvent::ADD_ICE_CANDIDATE_SUCCEEDED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_caller));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_callee));
+}
+
+#ifndef WEBRTC_ANDROID
+#ifdef WEBRTC_HAVE_SCTP
+// Test that the usage pattern bits for adding remote (private IPv6) candidates
+// are set when the remote candidates are retrieved from the Offer SDP instead
+// of trickled ICE messages.
+TEST_F(PeerConnectionUsageHistogramTest,
+       AddRemoteCandidatesFromRemoteDescription) {
+  // We construct the following data-channel-only scenario. The caller collects
+  // IPv6 private local candidates and appends them in the Offer as in
+  // non-trickled sessions. The callee collects mDNS candidates that are not
+  // contained in the Answer as in Trickle ICE. Only the Offer and Answer are
+  // signaled and we expect a connection with prflx remote candidates at the
+  // caller side.
+  auto caller = CreatePeerConnectionWithPrivateIpv6LocalAddresses();
+  RTCConfiguration config;
+  config.sdp_semantics = SdpSemantics::kUnifiedPlan;
+  auto callee = CreatePeerConnectionWithMdns(config);
+  caller->CreateDataChannel("test_channel");
+  ASSERT_TRUE(caller->SetLocalDescription(caller->CreateOffer()));
+  // Wait until the gathering completes so that the session description would
+  // have contained ICE candidates.
+  EXPECT_EQ_WAIT(webrtc::PeerConnectionInterface::kIceGatheringComplete,
+                 caller->ice_gathering_state(), kDefaultTimeout);
+  EXPECT_TRUE(caller->observer()->candidate_gathered());
+  // Get the current offer that contains candidates and pass it to the callee.
+  //
+  // Note that we cannot use CloneSessionDescription on `cur_offer` to obtain an
+  // SDP with candidates. The method above does not strictly copy everything, in
+  // particular, not copying the ICE candidates.
+  // TODO(qingsi): Technically, this is a bug. Fix it.
+  auto cur_offer = caller->pc()->local_description();
+  ASSERT_TRUE(cur_offer);
+  std::string sdp_with_candidates_str;
+  cur_offer->ToString(&sdp_with_candidates_str);
+  auto offer = std::make_unique<JsepSessionDescription>(SdpType::kOffer);
+  ASSERT_TRUE(SdpDeserialize(sdp_with_candidates_str, offer.get(),
+                             nullptr /* error */));
+  ASSERT_TRUE(callee->SetRemoteDescription(std::move(offer)));
+
+  // By default, the Answer created does not contain ICE candidates.
+  auto answer = callee->CreateAnswer();
+  callee->SetLocalDescription(CloneSessionDescription(answer.get()));
+  caller->SetRemoteDescription(std::move(answer));
+  EXPECT_TRUE_WAIT(caller->IsConnected(), kDefaultTimeout);
+  EXPECT_TRUE_WAIT(callee->IsConnected(), kDefaultTimeout);
+  // The callee needs to process the open message to have the data channel open.
+  EXPECT_TRUE_WAIT(callee->observer()->last_datachannel_ != nullptr,
+                   kDefaultTimeout);
+  caller->pc()->Close();
+  callee->pc()->Close();
+
+  // The caller should not have added any remote candidate either via
+  // AddIceCandidate or from the remote description. Also, the caller connects
+  // with the callee via a prflx candidate and hence no direct connection bit
+  // should be set.
+  int expected_fingerprint_caller = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::PRIVATE_CANDIDATE_COLLECTED,
+       UsageEvent::IPV6_CANDIDATE_COLLECTED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::CLOSE_CALLED});
+
+  int expected_fingerprint_callee = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::SET_REMOTE_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::MDNS_CANDIDATE_COLLECTED,
+       UsageEvent::REMOTE_CANDIDATE_ADDED,
+       UsageEvent::REMOTE_PRIVATE_CANDIDATE_ADDED,
+       UsageEvent::REMOTE_IPV6_CANDIDATE_ADDED, UsageEvent::ICE_STATE_CONNECTED,
+       UsageEvent::DIRECT_CONNECTION_SELECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(2, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_caller));
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumEvents(kUsagePatternMetric,
+                                                 expected_fingerprint_callee));
+}
+
+TEST_F(PeerConnectionUsageHistogramTest, NotableUsageNoted) {
+  auto caller = CreatePeerConnection();
+  caller->CreateDataChannel("foo");
+  caller->GenerateOfferAndCollectCandidates();
+  caller->pc()->Close();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  EXPECT_METRIC_TRUE(
+      expected_fingerprint == ObservedFingerprint() ||
+      (expected_fingerprint |
+       static_cast<int>(UsageEvent::PRIVATE_CANDIDATE_COLLECTED)) ==
+          ObservedFingerprint());
+  EXPECT_METRIC_EQ(absl::make_optional(ObservedFingerprint()),
+                   caller->observer()->interesting_usage_detected());
+}
+
+TEST_F(PeerConnectionUsageHistogramTest, NotableUsageOnEventFiring) {
+  auto caller = CreatePeerConnection();
+  caller->CreateDataChannel("foo");
+  caller->GenerateOfferAndCollectCandidates();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED});
+  EXPECT_METRIC_EQ(0, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  caller->GetInternalPeerConnection()->RequestUsagePatternReportForTesting();
+  EXPECT_METRIC_EQ_WAIT(1, webrtc::metrics::NumSamples(kUsagePatternMetric),
+                        kDefaultTimeout);
+  EXPECT_METRIC_TRUE(
+      expected_fingerprint == ObservedFingerprint() ||
+      (expected_fingerprint |
+       static_cast<int>(UsageEvent::PRIVATE_CANDIDATE_COLLECTED)) ==
+          ObservedFingerprint());
+  EXPECT_METRIC_EQ(absl::make_optional(ObservedFingerprint()),
+                   caller->observer()->interesting_usage_detected());
+}
+
+TEST_F(PeerConnectionUsageHistogramTest,
+       NoNotableUsageOnEventFiringAfterClose) {
+  auto caller = CreatePeerConnection();
+  caller->CreateDataChannel("foo");
+  caller->GenerateOfferAndCollectCandidates();
+  int expected_fingerprint = MakeUsageFingerprint(
+      {UsageEvent::DATA_ADDED, UsageEvent::SET_LOCAL_DESCRIPTION_SUCCEEDED,
+       UsageEvent::CANDIDATE_COLLECTED, UsageEvent::CLOSE_CALLED});
+  EXPECT_METRIC_EQ(0, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  caller->pc()->Close();
+  EXPECT_METRIC_EQ(1, webrtc::metrics::NumSamples(kUsagePatternMetric));
+  caller->GetInternalPeerConnection()->RequestUsagePatternReportForTesting();
+  caller->observer()->ClearInterestingUsageDetector();
+  EXPECT_METRIC_EQ_WAIT(2, webrtc::metrics::NumSamples(kUsagePatternMetric),
+                        kDefaultTimeout);
+  EXPECT_METRIC_TRUE(
+      expected_fingerprint == ObservedFingerprint() ||
+      (expected_fingerprint |
+       static_cast<int>(UsageEvent::PRIVATE_CANDIDATE_COLLECTED)) ==
+          ObservedFingerprint());
+  // After close, the usage-detection callback should NOT have been called.
+  EXPECT_METRIC_FALSE(caller->observer()->interesting_usage_detected());
+}
+#endif
+#endif
+
+}  // namespace webrtc