Feed v2: Log UMA EngagementType

- Plumb actions from FeedStreamSurface over to MetricsReporter
- Port EngagementType reporting from FeedLoggingBridge to
  work with feed v2.

Bug: 1044139
Change-Id: Ia6478ddcfa25445c15a8874aad20bfccf9fcaad1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2137854
Commit-Queue: Dan H <harringtond@chromium.org>
Reviewed-by: Carlos Knippschild <carlosk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757665}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/v2/FeedStreamSurface.java

@@ -138,6 +138,9 @@ public class FeedStreamSurface implements SurfaceActionsHandler, FeedActionsHand
         void reportManageInterests(long nativeFeedStreamSurface, FeedStreamSurface caller);
         // TODO(jianli): Call this function at the appropriate time.
         void reportContextMenuOpened(long nativeFeedStreamSurface, FeedStreamSurface caller);
+        // TODO(jianli): Call this function at the appropriate time.
+        void reportStreamScrolled(
+                long nativeFeedStreamSurface, FeedStreamSurface caller, int distanceDp);
         void loadMore(long nativeFeedStreamSurface, FeedStreamSurface caller);
         void processThereAndBackAgain(
                 long nativeFeedStreamSurface, FeedStreamSurface caller, byte[] data);

chrome/browser/android/feed/v2/feed_stream_surface.cc

@@ -4,6 +4,8 @@
 
 #include "chrome/browser/android/feed/v2/feed_stream_surface.h"
 
+#include <vector>
+
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "chrome/android/chrome_jni_headers/FeedStreamSurface_jni.h"
@@ -93,37 +95,44 @@ void FeedStreamSurface::ReportNavigationStarted(
     const JavaParamRef<jobject>& obj,
     const JavaParamRef<jstring>& url,
     jboolean in_new_tab) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportNavigationStarted();
 }
 
 void FeedStreamSurface::ReportNavigationDone(JNIEnv* env,
                                              const JavaParamRef<jobject>& obj,
                                              const JavaParamRef<jstring>& url,
                                              jboolean in_new_tab) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportNavigationDone();
 }
 
 void FeedStreamSurface::ReportContentRemoved(JNIEnv* env,
                                              const JavaParamRef<jobject>& obj) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportContentRemoved();
 }
 
 void FeedStreamSurface::ReportNotInterestedIn(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportNotInterestedIn();
 }
 
 void FeedStreamSurface::ReportManageInterests(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportManageInterests();
 }
 
 void FeedStreamSurface::ReportContextMenuOpened(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
-  // TODO(harringtond): Implement this.
+  feed_stream_api_->ReportContextMenuOpened();
+}
+
+void FeedStreamSurface::ReportStreamScrolled(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    int distance_dp) {
+  feed_stream_api_->ReportStreamScrolled(distance_dp);
 }
 
 }  // namespace feed

chrome/browser/android/feed/v2/feed_stream_surface.h

@@ -85,6 +85,11 @@ class FeedStreamSurface : public FeedStreamApi::SurfaceInterface {
   void ReportContextMenuOpened(JNIEnv* env,
                                const base::android::JavaParamRef<jobject>& obj);
 
+  // The user scrolled the feed by |distance_dp| and then stopped.
+  void ReportStreamScrolled(JNIEnv* env,
+                            const base::android::JavaParamRef<jobject>& obj,
+                            int distance_dp);
+
  private:
   base::android::ScopedJavaGlobalRef<jobject> java_ref_;
   FeedStreamApi* feed_stream_api_;

components/feed/core/v2/BUILD.gn

@@ -80,6 +80,7 @@ source_set("core_unit_tests") {
     "feed_network_impl_unittest.cc",
     "feed_store_unittest.cc",
     "feed_stream_unittest.cc",
+    "metrics_reporter_unittest.cc",
     "proto_util_unittest.cc",
     "request_throttler_unittest.cc",
     "stream_model_unittest.cc",

components/feed/core/v2/feed_stream.cc

@@ -19,6 +19,7 @@
 #include "components/feed/core/v2/enums.h"
 #include "components/feed/core/v2/feed_network.h"
 #include "components/feed/core/v2/feed_store.h"
+#include "components/feed/core/v2/metrics_reporter.h"
 #include "components/feed/core/v2/refresh_task_scheduler.h"
 #include "components/feed/core/v2/scheduling.h"
 #include "components/feed/core/v2/stream_model.h"
@@ -203,6 +204,7 @@ FeedStream::WireResponseTranslator::TranslateWireResponse(
 
 FeedStream::FeedStream(RefreshTaskScheduler* refresh_task_scheduler,
                        EventObserver* stream_event_observer,
+                       MetricsReporter* metrics_reporter,
                        Delegate* delegate,
                        PrefService* profile_prefs,
                        FeedNetwork* feed_network,
@@ -212,6 +214,7 @@ FeedStream::FeedStream(RefreshTaskScheduler* refresh_task_scheduler,
                        const ChromeInfo& chrome_info)
     : refresh_task_scheduler_(refresh_task_scheduler),
       stream_event_observer_(stream_event_observer),
+      metrics_reporter_(metrics_reporter),
       delegate_(delegate),
       profile_prefs_(profile_prefs),
       feed_network_(feed_network),
@@ -460,4 +463,26 @@ void FeedStream::UnloadModel() {
   model_.reset();
 }
 
+void FeedStream::ReportNavigationStarted() {
+  metrics_reporter_->NavigationStarted();
+}
+void FeedStream::ReportNavigationDone() {
+  metrics_reporter_->NavigationDone();
+}
+void FeedStream::ReportContentRemoved() {
+  metrics_reporter_->ContentRemoved();
+}
+void FeedStream::ReportNotInterestedIn() {
+  metrics_reporter_->NotInterestedIn();
+}
+void FeedStream::ReportManageInterests() {
+  metrics_reporter_->ManageInterests();
+}
+void FeedStream::ReportContextMenuOpened() {
+  metrics_reporter_->ContextMenuOpened();
+}
+void FeedStream::ReportStreamScrolled(int distance_dp) {
+  metrics_reporter_->StreamScrolled(distance_dp);
+}
+
 }  // namespace feed

components/feed/core/v2/feed_stream.h

@@ -31,10 +31,11 @@ class TickClock;
 }  // namespace base
 
 namespace feed {
-class FeedStore;
-class StreamModel;
 class FeedNetwork;
+class FeedStore;
+class MetricsReporter;
 class RefreshTaskScheduler;
+class StreamModel;
 struct StreamModelUpdateRequest;
 
 // Implements FeedStreamApi. |FeedStream| additionally exposes functionality
@@ -77,6 +78,7 @@ class FeedStream : public FeedStreamApi,
 
   FeedStream(RefreshTaskScheduler* refresh_task_scheduler,
              EventObserver* stream_event_observer,
+             MetricsReporter* metrics_reporter,
              Delegate* delegate,
              PrefService* profile_prefs,
              FeedNetwork* feed_network,
@@ -105,6 +107,14 @@ class FeedStream : public FeedStreamApi,
   bool CommitEphemeralChange(EphemeralChangeId id) override;
   bool RejectEphemeralChange(EphemeralChangeId id) override;
 
+  void ReportNavigationStarted() override;
+  void ReportNavigationDone() override;
+  void ReportContentRemoved() override;
+  void ReportNotInterestedIn() override;
+  void ReportManageInterests() override;
+  void ReportContextMenuOpened() override;
+  void ReportStreamScrolled(int distance_dp) override;
+
   // offline_pages::TaskQueue::Delegate.
   void OnTaskQueueIsIdle() override;
 
@@ -190,6 +200,7 @@ class FeedStream : public FeedStreamApi,
 
   RefreshTaskScheduler* refresh_task_scheduler_;
   EventObserver* stream_event_observer_;
+  MetricsReporter* metrics_reporter_;
   Delegate* delegate_;
   PrefService* profile_prefs_;
   FeedNetwork* feed_network_;

components/feed/core/v2/feed_stream_unittest.cc

@@ -22,6 +22,7 @@
 #include "components/feed/core/proto/v2/wire/request.pb.h"
 #include "components/feed/core/shared_prefs/pref_names.h"
 #include "components/feed/core/v2/feed_network.h"
+#include "components/feed/core/v2/metrics_reporter.h"
 #include "components/feed/core/v2/refresh_task_scheduler.h"
 #include "components/feed/core/v2/scheduling.h"
 #include "components/feed/core/v2/stream_model.h"
@@ -296,9 +297,10 @@ class FeedStreamTest : public testing::Test, public FeedStream::Delegate {
     chrome_info.channel = version_info::Channel::STABLE;
     chrome_info.version = base::Version({99, 1, 9911, 2});
     stream_ = std::make_unique<FeedStream>(
-        &refresh_scheduler_, &event_observer_, this, &profile_prefs_, &network_,
-        store_.get(), task_environment_.GetMockClock(),
-        task_environment_.GetMockTickClock(), chrome_info);
+        &refresh_scheduler_, &event_observer_, &metrics_reporter_, this,
+        &profile_prefs_, &network_, store_.get(),
+        task_environment_.GetMockClock(), task_environment_.GetMockTickClock(),
+        chrome_info);
 
     // Set the user classifier.
     auto user_classifier = std::make_unique<TestUserClassifier>(
@@ -351,6 +353,7 @@ class FeedStreamTest : public testing::Test, public FeedStream::Delegate {
       base::test::TaskEnvironment::TimeSource::MOCK_TIME};
   TestUserClassifier* user_classifier_;
   TestEventObserver event_observer_;
+  MetricsReporter metrics_reporter_{task_environment_.GetMockTickClock()};
   TestingPrefServiceSimple profile_prefs_;
   TestFeedNetwork network_;
   TestWireResponseTranslator response_translator_;

components/feed/core/v2/metrics_reporter.cc

@@ -3,10 +3,108 @@
 // found in the LICENSE file.
 #include "components/feed/core/v2/metrics_reporter.h"
 
+#include <cmath>
+
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
 
 namespace feed {
+namespace {
+using feed::internal::FeedEngagementType;
+
+void ReportEngagementTypeHistogram(FeedEngagementType engagement_type) {
+  UMA_HISTOGRAM_ENUMERATION("ContentSuggestions.Feed.EngagementType",
+                            engagement_type);
+}
+
+}  // namespace
+
+MetricsReporter::MetricsReporter(const base::TickClock* clock)
+    : clock_(clock) {}
+MetricsReporter::~MetricsReporter() = default;
+
+// Engagement Tracking.
+
+void MetricsReporter::RecordInteraction() {
+  RecordEngagement(/*scroll_distance_dp=*/0, /*interacted=*/true);
+  ReportEngagementTypeHistogram(FeedEngagementType::kFeedInteracted);
+}
+
+void MetricsReporter::RecordEngagement(int scroll_distance_dp,
+                                       bool interacted) {
+  scroll_distance_dp = std::abs(scroll_distance_dp);
+  // Determine if this interaction is part of a new 'session'.
+  auto now = clock_->NowTicks();
+  const base::TimeDelta kVisitTimeout = base::TimeDelta::FromMinutes(5);
+  if (now - visit_start_time_ > kVisitTimeout) {
+    engaged_reported_ = false;
+    engaged_simple_reported_ = false;
+  }
+  // Reset the last active time for session measurement.
+  visit_start_time_ = now;
+
+  // Report the user as engaged-simple if they have scrolled any amount or
+  // interacted with the card, and we have not already reported it for this
+  // chrome run.
+  if (!engaged_simple_reported_ && (scroll_distance_dp > 0 || interacted)) {
+    ReportEngagementTypeHistogram(FeedEngagementType::kFeedEngagedSimple);
+    engaged_simple_reported_ = true;
+  }
+
+  // Report the user as engaged if they have scrolled more than the threshold or
+  // interacted with the card, and we have not already reported it this chrome
+  // run.
+  const int kMinScrollThresholdDp = 160;  // 1 inch.
+  if (!engaged_reported_ &&
+      (scroll_distance_dp > kMinScrollThresholdDp || interacted)) {
+    ReportEngagementTypeHistogram(FeedEngagementType::kFeedEngaged);
+    engaged_reported_ = true;
+  }
+}
+
+void MetricsReporter::StreamScrolled(int distance_dp) {
+  RecordEngagement(distance_dp, /*interacted=*/false);
+
+  if (!scrolled_reported_) {
+    ReportEngagementTypeHistogram(FeedEngagementType::kFeedScrolled);
+    scrolled_reported_ = true;
+  }
+}
+
+void MetricsReporter::NavigationStarted() {
+  // TODO(harringtond): Add user actions.
+  // Report Feed_OpeningContent
+  RecordInteraction();
+}
+
+void MetricsReporter::NavigationDone() {
+  // TODO(harringtond): Use this or remove it.
+}
+
+void MetricsReporter::ContentRemoved() {
+  // TODO(harringtond): Add user actions.
+  // Report Feed_RemovedContent
+  RecordInteraction();
+}
+
+void MetricsReporter::NotInterestedIn() {
+  // TODO(harringtond): Add user actions.
+  // Report Feed_NotInterestedIn
+  RecordInteraction();
+}
+
+void MetricsReporter::ManageInterests() {
+  // TODO(harringtond): Add user actions.
+  // Report Feed_ManageInterests
+  RecordInteraction();
+}
+
+void MetricsReporter::ContextMenuOpened() {
+  // TODO(harringtond): Add user actions.
+  // Report Feed_OpenedContextMenu
+}
 
 void MetricsReporter::NetworkRequestComplete(NetworkRequestType type,
                                              int http_status_code) {

components/feed/core/v2/metrics_reporter.h

@@ -5,24 +5,71 @@
 #ifndef COMPONENTS_FEED_CORE_V2_METRICS_REPORTER_H_
 #define COMPONENTS_FEED_CORE_V2_METRICS_REPORTER_H_
 
+#include "base/time/time.h"
 #include "components/feed/core/v2/enums.h"
 #include "components/feed/core/v2/feed_stream.h"
 
+namespace base {
+class TickClock;
+}  // namespace base
+
 namespace feed {
 
+namespace internal {
+// This enum is used for a UMA histogram. Keep in sync with FeedEngagementType
+// in enums.xml.
+enum class FeedEngagementType {
+  kFeedEngaged = 0,
+  kFeedEngagedSimple = 1,
+  kFeedInteracted = 2,
+  kFeedScrolled = 3,
+  kMaxValue = FeedEngagementType::kFeedScrolled,
+};
+}  // namespace internal
+
 // Reports UMA metrics for feed.
 class MetricsReporter : public FeedStream::EventObserver {
  public:
+  explicit MetricsReporter(const base::TickClock* clock);
+  virtual ~MetricsReporter();
+  MetricsReporter(const MetricsReporter&) = delete;
+  MetricsReporter& operator=(const MetricsReporter&) = delete;
+
+  // User interactions.
+
+  void NavigationStarted();
+  void NavigationDone();
+  void ContentRemoved();
+  void NotInterestedIn();
+  void ManageInterests();
+  void ContextMenuOpened();
+  // Indicates the user scrolled the feed by |distance_dp| and then stopped
+  // scrolling.
+  void StreamScrolled(int distance_dp);
+
   // Network metrics.
+
   static void NetworkRequestComplete(NetworkRequestType type,
                                      int http_status_code);
 
   // FeedStream::EventObserver.
+
   void OnLoadStream(LoadStreamStatus load_from_store_status,
                     LoadStreamStatus final_status) override;
   void OnMaybeTriggerRefresh(TriggerType trigger,
                              bool clear_all_before_refresh) override;
   void OnClearAll(base::TimeDelta time_since_last_clear) override;
+
+ private:
+  void RecordEngagement(int scroll_distance_dp, bool interacted);
+  void RecordInteraction();
+
+  const base::TickClock* clock_;
+
+  base::TimeTicks visit_start_time_;
+  bool engaged_simple_reported_ = false;
+  bool engaged_reported_ = false;
+  bool scrolled_reported_ = false;
 };
 }  // namespace feed
 

components/feed/core/v2/metrics_reporter_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 "components/feed/core/v2/metrics_reporter.h"
+
+#include <map>
+
+#include "base/test/metrics/histogram_tester.h"
+#include "base/test/simple_test_tick_clock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace feed {
+using feed::internal::FeedEngagementType;
+const base::TimeDelta kEpsilon = base::TimeDelta::FromMilliseconds(1);
+
+class MetricsReporterTest : public testing::Test {
+ protected:
+  std::map<FeedEngagementType, int> ReportedEngagementType() {
+    std::map<FeedEngagementType, int> result;
+    for (const auto& bucket :
+         histogram_.GetAllSamples("ContentSuggestions.Feed.EngagementType")) {
+      result[static_cast<FeedEngagementType>(bucket.min)] += bucket.count;
+    }
+    return result;
+  }
+
+  base::SimpleTestTickClock clock_;
+  MetricsReporter reporter_{&clock_};
+  base::HistogramTester histogram_;
+};
+
+TEST_F(MetricsReporterTest, ScrollingSmall) {
+  reporter_.StreamScrolled(100);
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedScrolled, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, ScrollingCanTriggerEngaged) {
+  reporter_.StreamScrolled(161);
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedScrolled, 1},
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, OpeningContentIsInteracting) {
+  reporter_.NavigationStarted();
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedInteracted, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, RemovingContentIsInteracting) {
+  reporter_.ContentRemoved();
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedInteracted, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, NotInterestedInIsInteracting) {
+  reporter_.NotInterestedIn();
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedInteracted, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, ManageInterestsInIsInteracting) {
+  reporter_.ManageInterests();
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedInteracted, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, VisitsCanLastMoreThanFiveMinutes) {
+  reporter_.StreamScrolled(1);
+  clock_.Advance(base::TimeDelta::FromMinutes(5) - kEpsilon);
+  reporter_.NavigationStarted();
+  clock_.Advance(base::TimeDelta::FromMinutes(5) - kEpsilon);
+  reporter_.StreamScrolled(1);
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 1},
+      {FeedEngagementType::kFeedInteracted, 1},
+      {FeedEngagementType::kFeedScrolled, 1},
+      {FeedEngagementType::kFeedEngagedSimple, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+TEST_F(MetricsReporterTest, NewVisitAfterInactivity) {
+  reporter_.NavigationStarted();
+  reporter_.StreamScrolled(1);
+  clock_.Advance(base::TimeDelta::FromMinutes(5) + kEpsilon);
+  reporter_.NavigationStarted();
+  reporter_.StreamScrolled(1);
+
+  std::map<FeedEngagementType, int> want({
+      {FeedEngagementType::kFeedEngaged, 2},
+      {FeedEngagementType::kFeedInteracted, 2},
+      {FeedEngagementType::kFeedEngagedSimple, 2},
+      {FeedEngagementType::kFeedScrolled, 1},
+  });
+  EXPECT_EQ(want, ReportedEngagementType());
+}
+
+}  // namespace feed

components/feed/core/v2/public/feed_service.cc

@@ -11,6 +11,7 @@
 #include "components/feed/core/v2/feed_network_impl.h"
 #include "components/feed/core/v2/feed_store.h"
 #include "components/feed/core/v2/feed_stream.h"
+#include "components/feed/core/v2/metrics_reporter.h"
 #include "components/feed/core/v2/refresh_task_scheduler.h"
 #include "net/base/network_change_notifier.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
@@ -88,17 +89,18 @@ FeedService::FeedService(
       refresh_task_scheduler_(std::move(refresh_task_scheduler)) {
   stream_delegate_ = std::make_unique<StreamDelegateImpl>(local_state);
   network_delegate_ = std::make_unique<NetworkDelegateImpl>(delegate_.get());
+  metrics_reporter_ =
+      std::make_unique<MetricsReporter>(base::DefaultTickClock::GetInstance());
   feed_network_ = std::make_unique<FeedNetworkImpl>(
       network_delegate_.get(), identity_manager, api_key, url_loader_factory,
       base::DefaultTickClock::GetInstance(), profile_prefs);
   store_ = std::make_unique<FeedStore>(std::move(database));
 
   stream_ = std::make_unique<FeedStream>(
-      refresh_task_scheduler_.get(),
-      nullptr,  // TODO(harringtond): Implement EventObserver.
-      stream_delegate_.get(), profile_prefs, feed_network_.get(), store_.get(),
-      base::DefaultClock::GetInstance(), base::DefaultTickClock::GetInstance(),
-      chrome_info);
+      refresh_task_scheduler_.get(), metrics_reporter_.get(),
+      metrics_reporter_.get(), stream_delegate_.get(), profile_prefs,
+      feed_network_.get(), store_.get(), base::DefaultClock::GetInstance(),
+      base::DefaultTickClock::GetInstance(), chrome_info);
 
   stream_delegate_->Initialize(static_cast<FeedStream*>(stream_.get()));
 

components/feed/core/v2/public/feed_service.h

@@ -31,6 +31,7 @@ class IdentityManager;
 
 namespace feed {
 class RefreshTaskScheduler;
+class MetricsReporter;
 class FeedNetwork;
 class FeedStore;
 
@@ -74,6 +75,7 @@ class FeedService : public KeyedService {
   // be null if |FeedStreamApi| is created externally.
   std::unique_ptr<Delegate> delegate_;
   std::unique_ptr<StreamDelegateImpl> stream_delegate_;
+  std::unique_ptr<MetricsReporter> metrics_reporter_;
   std::unique_ptr<NetworkDelegateImpl> network_delegate_;
   std::unique_ptr<FeedNetwork> feed_network_;
   std::unique_ptr<FeedStore> store_;

components/feed/core/v2/public/feed_stream_api.h

@@ -52,6 +52,16 @@ class FeedStreamApi {
   virtual bool CommitEphemeralChange(EphemeralChangeId id) = 0;
   // Rejects a change. Returns false if the change does not exist.
   virtual bool RejectEphemeralChange(EphemeralChangeId id) = 0;
+
+  // User interaction reporting. These should have no side-effects other than
+  // reporting metrics.
+  virtual void ReportNavigationStarted() = 0;
+  virtual void ReportNavigationDone() = 0;
+  virtual void ReportContentRemoved() = 0;
+  virtual void ReportNotInterestedIn() = 0;
+  virtual void ReportManageInterests() = 0;
+  virtual void ReportContextMenuOpened() = 0;
+  virtual void ReportStreamScrolled(int distance_dp) = 0;
 };
 
 }  // namespace feed