diff --git a/core/java/android/app/jank/JankTracker.java b/core/java/android/app/jank/JankTracker.java
new file mode 100644
index 0000000..df422e0
--- /dev/null
+++ b/core/java/android/app/jank/JankTracker.java
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.app.jank;
+
+import android.annotation.FlaggedApi;
+import android.annotation.NonNull;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.view.AttachedSurfaceControl;
+import android.view.Choreographer;
+import android.view.SurfaceControl;
+import android.view.View;
+import android.view.ViewTreeObserver;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.util.ArrayList;
+
+/**
+ * This class is responsible for registering callbacks that will receive JankData batches.
+ * It handles managing the background thread that JankData will be processed on. As well as acting
+ * as an intermediary between widgets and the state tracker, routing state changes to the tracker.
+ * @hide
+ */
+@FlaggedApi(Flags.FLAG_DETAILED_APP_JANK_METRICS_API)
+public class JankTracker {
+
+    // Tracks states reported by widgets.
+    private StateTracker mStateTracker;
+    // Processes JankData batches and associates frames to widget states.
+    private JankDataProcessor mJankDataProcessor;
+
+    // Background thread responsible for processing JankData batches.
+    private HandlerThread mHandlerThread = new HandlerThread("AppJankTracker");
+    private Handler mHandler = null;
+
+    // Needed so we know when the view is attached to a window.
+    private ViewTreeObserver mViewTreeObserver;
+
+    // Handle to a registered OnJankData listener.
+    private SurfaceControl.OnJankDataListenerRegistration mJankDataListenerRegistration;
+
+    // The interface to the windowing system that enables us to register for JankData.
+    private AttachedSurfaceControl mSurfaceControl;
+    // Name of the activity that is currently tracking Jank metrics.
+    private String mActivityName;
+    // The apps uid.
+    private int mAppUid;
+    // View that gives us access to ViewTreeObserver.
+    private View mDecorView;
+
+    /**
+     * Set by the activity to enable or disable jank tracking. Activities may disable tracking if
+     * they are paused or not enable tracking if they are not visible or if the app category is not
+     * set.
+     */
+    private boolean mTrackingEnabled = false;
+    /**
+     * Set to true once listeners are registered and JankData will start to be received. Both
+     * mTrackingEnabled and mListenersRegistered need to be true for JankData to be processed.
+     */
+    private boolean mListenersRegistered = false;
+
+
+    public JankTracker(Choreographer choreographer, View decorView) {
+        mStateTracker = new StateTracker(choreographer);
+        mJankDataProcessor = new JankDataProcessor(mStateTracker);
+        mDecorView = decorView;
+        mHandlerThread.start();
+        registerWindowListeners();
+    }
+
+    public void setActivityName(@NonNull String activityName) {
+        mActivityName = activityName;
+    }
+
+    public void setAppUid(int uid) {
+        mAppUid = uid;
+    }
+
+    /**
+     * Will add the widget category, id and state as a UI state to associate frames to it.
+     * @param widgetCategory preselected general widget category
+     * @param widgetId developer defined widget id if available.
+     * @param widgetState the current active widget state.
+     */
+    public void addUiState(String widgetCategory, String widgetId, String widgetState) {
+        if (!shouldTrack()) return;
+
+        mStateTracker.putState(widgetCategory, widgetId, widgetState);
+    }
+
+    /**
+     * Will remove the widget category, id and state as a ui state and no longer attribute frames
+     * to it.
+     * @param widgetCategory preselected general widget category
+     * @param widgetId developer defined widget id if available.
+     * @param widgetState no longer active widget state.
+     */
+    public void removeUiState(String widgetCategory, String widgetId, String widgetState) {
+        if (!shouldTrack()) return;
+
+        mStateTracker.removeState(widgetCategory, widgetId, widgetState);
+    }
+
+    /**
+     * Call to update a jank state to a different state.
+     * @param widgetCategory preselected general widget category.
+     * @param widgetId developer defined widget id if available.
+     * @param currentState current state of the widget.
+     * @param nextState the state the widget will be in.
+     */
+    public void updateUiState(String widgetCategory, String widgetId, String currentState,
+            String nextState) {
+        if (!shouldTrack()) return;
+
+        mStateTracker.updateState(widgetCategory, widgetId, currentState, nextState);
+    }
+
+    /**
+     * Will enable jank tracking, and add the activity as a state to associate frames to.
+     */
+    public void enableAppJankTracking() {
+        // Add the activity as a state, this will ensure we track frames to the activity without the
+        // need of a decorated widget to be used.
+        // TODO b/376116199 replace "NONE" with UNSPECIFIED once the API changes are merged.
+        mStateTracker.putState("NONE", mActivityName, "NONE");
+        mTrackingEnabled = true;
+    }
+
+    /**
+     * Will disable jank tracking, and remove the activity as a state to associate frames to.
+     */
+    public void disableAppJankTracking() {
+        mTrackingEnabled = false;
+        // TODO b/376116199 replace "NONE" with UNSPECIFIED once the API changes are merged.
+        mStateTracker.removeState("NONE", mActivityName, "NONE");
+    }
+
+    /**
+     * Retrieve all pending widget states, this is intended for testing purposes only.
+     * @param stateDataList the ArrayList that will be populated with the pending states.
+     */
+    @VisibleForTesting
+    public void getAllUiStates(@NonNull ArrayList<StateTracker.StateData> stateDataList) {
+        mStateTracker.retrieveAllStates(stateDataList);
+    }
+
+    /**
+     * Only intended to be used by tests, the runnable that registers the listeners may not run
+     * in time for tests to pass. This forces them to run immediately.
+     */
+    @VisibleForTesting
+    public void forceListenerRegistration() {
+        mSurfaceControl = mDecorView.getRootSurfaceControl();
+        registerForJankData();
+        // TODO b/376116199 Check if registration is good.
+        mListenersRegistered = true;
+    }
+
+    private void registerForJankData() {
+        if (mSurfaceControl == null) return;
+        /*
+        TODO b/376115668 Register for JankData batches from new JankTracking API
+         */
+    }
+
+    private boolean shouldTrack() {
+        return mTrackingEnabled && mListenersRegistered;
+    }
+
+    /**
+     * Need to know when the decor view gets attached to the window in order to get
+     * AttachedSurfaceControl. In order to register a callback for OnJankDataListener
+     * AttachedSurfaceControl needs to be created which only happens after onWindowAttached is
+     * called. This is why there is a delay in posting the runnable.
+     */
+    private void registerWindowListeners() {
+        if (mDecorView == null) return;
+        mViewTreeObserver = mDecorView.getViewTreeObserver();
+        mViewTreeObserver.addOnWindowAttachListener(new ViewTreeObserver.OnWindowAttachListener() {
+            @Override
+            public void onWindowAttached() {
+                getHandler().postDelayed(new Runnable() {
+                    @Override
+                    public void run() {
+                        forceListenerRegistration();
+                    }
+                }, 1000);
+            }
+
+            @Override
+            public void onWindowDetached() {
+                // TODO b/376116199  do we un-register the callback or just not process the data.
+            }
+        });
+    }
+
+    private Handler getHandler() {
+        if (mHandler == null) {
+            mHandler = new Handler(mHandlerThread.getLooper());
+        }
+        return mHandler;
+    }
+}
diff --git a/tests/AppJankTest/src/android/app/jank/tests/JankTrackerTest.java b/tests/AppJankTest/src/android/app/jank/tests/JankTrackerTest.java
new file mode 100644
index 0000000..a3e5533
--- /dev/null
+++ b/tests/AppJankTest/src/android/app/jank/tests/JankTrackerTest.java
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.app.jank.tests;
+
+import static org.junit.Assert.assertEquals;
+
+import android.app.jank.Flags;
+import android.app.jank.JankTracker;
+import android.app.jank.StateTracker;
+import android.platform.test.annotations.RequiresFlagsEnabled;
+import android.platform.test.flag.junit.CheckFlagsRule;
+import android.platform.test.flag.junit.DeviceFlagsValueProvider;
+import android.view.Choreographer;
+import android.view.View;
+
+import androidx.test.annotation.UiThreadTest;
+import androidx.test.core.app.ActivityScenario;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.ArrayList;
+
+@RunWith(AndroidJUnit4.class)
+public class JankTrackerTest {
+    private Choreographer mChoreographer;
+    private JankTracker mJankTracker;
+
+    @Rule
+    public final CheckFlagsRule mCheckFlagsRule = DeviceFlagsValueProvider.createCheckFlagsRule();
+
+    /**
+     * Start an empty activity so decore view is not null when creating the JankTracker instance.
+     */
+    private static ActivityScenario<EmptyActivity> sEmptyActivityRule;
+
+    private static String sActivityName;
+
+    private static View sActivityDecorView;
+
+    @BeforeClass
+    public static void classSetup() {
+        sEmptyActivityRule = ActivityScenario.launch(EmptyActivity.class);
+        sEmptyActivityRule.onActivity(activity -> {
+            sActivityDecorView = activity.getWindow().getDecorView();
+            sActivityName = activity.toString();
+        });
+    }
+
+    @AfterClass
+    public static void classTearDown() {
+        sEmptyActivityRule.close();
+    }
+
+    @Before
+    @UiThreadTest
+    public void setup() {
+        mChoreographer = Choreographer.getInstance();
+        mJankTracker = new JankTracker(mChoreographer, sActivityDecorView);
+        mJankTracker.setActivityName(sActivityName);
+    }
+
+    /**
+     * When jank tracking is enabled the activity name should be added as a state to associate
+     * frames to it.
+     */
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DETAILED_APP_JANK_METRICS_API)
+    public void jankTracking_WhenEnabled_ActivityAdded() {
+        mJankTracker.enableAppJankTracking();
+
+        ArrayList<StateTracker.StateData> stateData = new ArrayList<>();
+        mJankTracker.getAllUiStates(stateData);
+
+        assertEquals(1, stateData.size());
+
+        StateTracker.StateData firstState = stateData.getFirst();
+
+        assertEquals(sActivityName, firstState.mWidgetId);
+    }
+
+    /**
+     * No states should be added when tracking is disabled.
+     */
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DETAILED_APP_JANK_METRICS_API)
+    public void jankTrackingDisabled_StatesShouldNot_BeAddedToTracker() {
+        mJankTracker.disableAppJankTracking();
+
+        mJankTracker.addUiState("FAKE_CATEGORY", "FAKE_ID",
+                "FAKE_STATE");
+
+        ArrayList<StateTracker.StateData> stateData = new ArrayList<>();
+        mJankTracker.getAllUiStates(stateData);
+
+        assertEquals(0, stateData.size());
+    }
+
+    /**
+     * The activity name as well as the test state should be added for frame association.
+     */
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DETAILED_APP_JANK_METRICS_API)
+    public void jankTrackingEnabled_StatesShould_BeAddedToTracker() {
+        mJankTracker.forceListenerRegistration();
+
+        mJankTracker.enableAppJankTracking();
+        mJankTracker.addUiState("FAKE_CATEGORY", "FAKE_ID",
+                "FAKE_STATE");
+
+        ArrayList<StateTracker.StateData> stateData = new ArrayList<>();
+        mJankTracker.getAllUiStates(stateData);
+
+        assertEquals(2, stateData.size());
+    }
+
+    /**
+     * Activity state should only be added once even if jank tracking is enabled multiple times.
+     */
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DETAILED_APP_JANK_METRICS_API)
+    public void jankTrackingEnabled_EnabledCalledTwice_ActivityStateOnlyAddedOnce() {
+        mJankTracker.enableAppJankTracking();
+
+        ArrayList<StateTracker.StateData> stateData = new ArrayList<>();
+        mJankTracker.getAllUiStates(stateData);
+
+        assertEquals(1, stateData.size());
+
+        stateData.clear();
+
+        mJankTracker.enableAppJankTracking();
+        mJankTracker.getAllUiStates(stateData);
+
+        assertEquals(1, stateData.size());
+    }
+}