[Media TTT] Use a listener pattern to notify about view removals.

In order to handle the swipe-to-dismiss gesture correctly, we need to
notify MediaTttSenderCoordinator about both a view timing out, and a
view being removed due to swipe. So, having the `onViewTimeout` Runnable
will no longer work.

This CL instead uses a listener interface to notify
`MediaTttSenderCoordinator` whenever the view has timed out / been
removed. A future CL will add the swipe-to-dismiss gesture. That gesture
will also trigger this new listener method, so that
MediaTttSenderCoordinator always stays up-to-date.

Bug: 262584940
Test: manual: verify media ttt chipbars with different IDs still works
(id1=triggered, then id2=almostClose. When id2 times out, id1 is
redisplayed, then also times out)
Test: atest MediaTttSenderCoordinatorTest
TemporaryViewDisplayControllerTest

Change-Id: I73c6235718f3b660ea416ca459ae777d8624a7be
diff --git a/packages/SystemUI/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinator.kt b/packages/SystemUI/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinator.kt
index 935f38d..be93c54 100644
--- a/packages/SystemUI/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinator.kt
+++ b/packages/SystemUI/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinator.kt
@@ -30,6 +30,7 @@
 import com.android.systemui.media.taptotransfer.common.MediaTttLogger
 import com.android.systemui.media.taptotransfer.common.MediaTttUtils
 import com.android.systemui.statusbar.CommandQueue
+import com.android.systemui.temporarydisplay.TemporaryViewDisplayController
 import com.android.systemui.temporarydisplay.ViewPriority
 import com.android.systemui.temporarydisplay.chipbar.ChipbarCoordinator
 import com.android.systemui.temporarydisplay.chipbar.ChipbarEndItem
@@ -54,6 +55,7 @@
 
     private var displayedState: ChipStateSender? = null
     // A map to store current chip state per id.
+    // TODO(b/265455911): Log whenever we add or remove from the store.
     private var stateMap: MutableMap<String, ChipStateSender> = mutableMapOf()
 
     private val commandQueueCallbacks =
@@ -102,10 +104,9 @@
         }
         uiEventLogger.logSenderStateChange(chipState)
 
-        stateMap.put(routeInfo.id, chipState)
         if (chipState == ChipStateSender.FAR_FROM_RECEIVER) {
             // No need to store the state since it is the default state
-            stateMap.remove(routeInfo.id)
+            removeIdFromStore(routeInfo.id)
             // Return early if we're not displaying a chip anyway
             val currentDisplayedState = displayedState ?: return
 
@@ -126,7 +127,9 @@
             displayedState = null
             chipbarCoordinator.removeView(routeInfo.id, removalReason)
         } else {
+            stateMap[routeInfo.id] = chipState
             displayedState = chipState
+            chipbarCoordinator.registerListener(displayListener)
             chipbarCoordinator.displayView(
                 createChipbarInfo(
                     chipState,
@@ -135,7 +138,7 @@
                     context,
                     logger,
                 )
-            ) { stateMap.remove(routeInfo.id) }
+            )
         }
     }
 
@@ -225,4 +228,14 @@
             onClickListener,
         )
     }
+
+    private val displayListener =
+        TemporaryViewDisplayController.Listener { id -> removeIdFromStore(id) }
+
+    private fun removeIdFromStore(id: String) {
+        stateMap.remove(id)
+        if (stateMap.isEmpty()) {
+            chipbarCoordinator.unregisterListener(displayListener)
+        }
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayController.kt b/packages/SystemUI/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayController.kt
index ad48e21..cf722ce 100644
--- a/packages/SystemUI/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayController.kt
+++ b/packages/SystemUI/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayController.kt
@@ -119,15 +119,26 @@
         dumpManager.registerNormalDumpable(this)
     }
 
+    private val listeners: MutableSet<Listener> = mutableSetOf()
+
+    /** Registers a listener. */
+    fun registerListener(listener: Listener) {
+        listeners.add(listener)
+    }
+
+    /** Unregisters a listener. */
+    fun unregisterListener(listener: Listener) {
+        listeners.remove(listener)
+    }
+
     /**
      * Displays the view with the provided [newInfo].
      *
      * This method handles inflating and attaching the view, then delegates to [updateView] to
      * display the correct information in the view.
-     * @param onViewTimeout a runnable that runs after the view timeout.
      */
     @Synchronized
-    fun displayView(newInfo: T, onViewTimeout: Runnable? = null) {
+    fun displayView(newInfo: T) {
         val timeout = accessibilityManager.getRecommendedTimeoutMillis(
             newInfo.timeoutMs,
             // Not all views have controls so FLAG_CONTENT_CONTROLS might be superfluous, but
@@ -146,14 +157,13 @@
             logger.logViewUpdate(newInfo)
             currentDisplayInfo.info = newInfo
             currentDisplayInfo.timeExpirationMillis = timeExpirationMillis
-            updateTimeout(currentDisplayInfo, timeout, onViewTimeout)
+            updateTimeout(currentDisplayInfo, timeout)
             updateView(newInfo, view)
             return
         }
 
         val newDisplayInfo = DisplayInfo(
             info = newInfo,
-            onViewTimeout = onViewTimeout,
             timeExpirationMillis = timeExpirationMillis,
             // Null values will be updated to non-null if/when this view actually gets displayed
             view = null,
@@ -196,7 +206,7 @@
     private fun showNewView(newDisplayInfo: DisplayInfo, timeout: Int) {
         logger.logViewAddition(newDisplayInfo.info)
         createAndAcquireWakeLock(newDisplayInfo)
-        updateTimeout(newDisplayInfo, timeout, newDisplayInfo.onViewTimeout)
+        updateTimeout(newDisplayInfo, timeout)
         inflateAndUpdateView(newDisplayInfo)
     }
 
@@ -227,19 +237,16 @@
     /**
      * Creates a runnable that will remove [displayInfo] in [timeout] ms from now.
      *
-     * @param onViewTimeout an optional runnable that will be run if the view times out.
      * @return a runnable that, when run, will *cancel* the view's timeout.
      */
-    private fun updateTimeout(displayInfo: DisplayInfo, timeout: Int, onViewTimeout: Runnable?) {
+    private fun updateTimeout(displayInfo: DisplayInfo, timeout: Int) {
         val cancelViewTimeout = mainExecutor.executeDelayed(
             {
                 removeView(displayInfo.info.id, REMOVAL_REASON_TIMEOUT)
-                onViewTimeout?.run()
             },
             timeout.toLong()
         )
 
-        displayInfo.onViewTimeout = onViewTimeout
         // Cancel old view timeout and re-set it.
         displayInfo.cancelViewTimeout?.run()
         displayInfo.cancelViewTimeout = cancelViewTimeout
@@ -317,6 +324,9 @@
         // event comes in while this view is animating out, we still display the new view
         // appropriately.
         activeViews.remove(displayInfo)
+        listeners.forEach {
+            it.onInfoPermanentlyRemoved(id)
+        }
 
         // No need to time the view out since it's already gone
         displayInfo.cancelViewTimeout?.run()
@@ -380,6 +390,9 @@
         invalidViews.forEach {
             activeViews.remove(it)
             logger.logViewExpiration(it.info)
+            listeners.forEach { listener ->
+                listener.onInfoPermanentlyRemoved(it.info.id)
+            }
         }
     }
 
@@ -436,6 +449,15 @@
         onAnimationEnd.run()
     }
 
+    /** A listener interface to be notified of various view events. */
+    fun interface Listener {
+        /**
+         * Called whenever a [DisplayInfo] with the given [id] has been removed and will never be
+         * displayed again (unless another call to [updateView] is made).
+         */
+        fun onInfoPermanentlyRemoved(id: String)
+    }
+
     /** A container for all the display-related state objects. */
     inner class DisplayInfo(
         /**
@@ -461,11 +483,6 @@
         var wakeLock: WakeLock?,
 
         /**
-         * See [displayView].
-         */
-        var onViewTimeout: Runnable?,
-
-        /**
          * A runnable that, when run, will cancel this view's timeout.
          *
          * Null if this info isn't currently being displayed.
diff --git a/packages/SystemUI/tests/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinatorTest.kt b/packages/SystemUI/tests/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinatorTest.kt
index f5b3959..1cdce99 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinatorTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/media/taptotransfer/sender/MediaTttSenderCoordinatorTest.kt
@@ -45,13 +45,17 @@
 import com.android.systemui.statusbar.CommandQueue
 import com.android.systemui.statusbar.VibratorHelper
 import com.android.systemui.statusbar.policy.ConfigurationController
+import com.android.systemui.temporarydisplay.TemporaryViewDisplayController
 import com.android.systemui.temporarydisplay.chipbar.ChipbarCoordinator
 import com.android.systemui.temporarydisplay.chipbar.ChipbarInfo
 import com.android.systemui.temporarydisplay.chipbar.ChipbarLogger
 import com.android.systemui.temporarydisplay.chipbar.FakeChipbarCoordinator
 import com.android.systemui.util.concurrency.FakeExecutor
 import com.android.systemui.util.mockito.any
+import com.android.systemui.util.mockito.argumentCaptor
+import com.android.systemui.util.mockito.capture
 import com.android.systemui.util.mockito.eq
+import com.android.systemui.util.mockito.mock
 import com.android.systemui.util.time.FakeSystemClock
 import com.android.systemui.util.view.ViewUtil
 import com.android.systemui.util.wakelock.WakeLockFake
@@ -61,6 +65,7 @@
 import org.junit.runner.RunWith
 import org.mockito.ArgumentCaptor
 import org.mockito.Mock
+import org.mockito.Mockito.atLeast
 import org.mockito.Mockito.never
 import org.mockito.Mockito.reset
 import org.mockito.Mockito.verify
@@ -161,9 +166,7 @@
             )
         underTest.start()
 
-        val callbackCaptor = ArgumentCaptor.forClass(CommandQueue.Callbacks::class.java)
-        verify(commandQueue).addCallback(callbackCaptor.capture())
-        commandQueueCallback = callbackCaptor.value!!
+        setCommandQueueCallback()
     }
 
     @Test
@@ -920,6 +923,172 @@
         verify(windowManager).removeView(any())
     }
 
+    @Test
+    fun newState_viewListenerRegistered() {
+        val mockChipbarCoordinator = mock<ChipbarCoordinator>()
+        underTest =
+            MediaTttSenderCoordinator(
+                mockChipbarCoordinator,
+                commandQueue,
+                context,
+                logger,
+                mediaTttFlags,
+                uiEventLogger,
+            )
+        underTest.start()
+        // Re-set the command queue callback since we've created a new [MediaTttSenderCoordinator]
+        // with a new callback.
+        setCommandQueueCallback()
+
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            routeInfo,
+            null,
+        )
+
+        verify(mockChipbarCoordinator).registerListener(any())
+    }
+
+    @Test
+    fun onInfoPermanentlyRemoved_viewListenerUnregistered() {
+        val mockChipbarCoordinator = mock<ChipbarCoordinator>()
+        underTest =
+            MediaTttSenderCoordinator(
+                mockChipbarCoordinator,
+                commandQueue,
+                context,
+                logger,
+                mediaTttFlags,
+                uiEventLogger,
+            )
+        underTest.start()
+        setCommandQueueCallback()
+
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            routeInfo,
+            null,
+        )
+
+        val listenerCaptor = argumentCaptor<TemporaryViewDisplayController.Listener>()
+        verify(mockChipbarCoordinator).registerListener(capture(listenerCaptor))
+
+        // WHEN the listener is notified that the view has been removed
+        listenerCaptor.value.onInfoPermanentlyRemoved(DEFAULT_ID)
+
+        // THEN the media coordinator unregisters the listener
+        verify(mockChipbarCoordinator).unregisterListener(listenerCaptor.value)
+    }
+
+    @Test
+    fun onInfoPermanentlyRemoved_wrongId_viewListenerNotUnregistered() {
+        val mockChipbarCoordinator = mock<ChipbarCoordinator>()
+        underTest =
+            MediaTttSenderCoordinator(
+                mockChipbarCoordinator,
+                commandQueue,
+                context,
+                logger,
+                mediaTttFlags,
+                uiEventLogger,
+            )
+        underTest.start()
+        setCommandQueueCallback()
+
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            routeInfo,
+            null,
+        )
+
+        val listenerCaptor = argumentCaptor<TemporaryViewDisplayController.Listener>()
+        verify(mockChipbarCoordinator).registerListener(capture(listenerCaptor))
+
+        // WHEN the listener is notified that a different view has been removed
+        listenerCaptor.value.onInfoPermanentlyRemoved("differentViewId")
+
+        // THEN the media coordinator doesn't unregister the listener
+        verify(mockChipbarCoordinator, never()).unregisterListener(listenerCaptor.value)
+    }
+
+    @Test
+    fun farFromReceiverState_viewListenerUnregistered() {
+        val mockChipbarCoordinator = mock<ChipbarCoordinator>()
+        underTest =
+            MediaTttSenderCoordinator(
+                mockChipbarCoordinator,
+                commandQueue,
+                context,
+                logger,
+                mediaTttFlags,
+                uiEventLogger,
+            )
+        underTest.start()
+        setCommandQueueCallback()
+
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            routeInfo,
+            null,
+        )
+
+        val listenerCaptor = argumentCaptor<TemporaryViewDisplayController.Listener>()
+        verify(mockChipbarCoordinator).registerListener(capture(listenerCaptor))
+
+        // WHEN we go to the FAR_FROM_RECEIVER state
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_FAR_FROM_RECEIVER,
+            routeInfo,
+            null
+        )
+
+        // THEN the media coordinator unregisters the listener
+        verify(mockChipbarCoordinator).unregisterListener(listenerCaptor.value)
+    }
+
+    @Test
+    fun statesWithDifferentIds_onInfoPermanentlyRemovedForOneId_viewListenerNotUnregistered() {
+        val mockChipbarCoordinator = mock<ChipbarCoordinator>()
+        underTest =
+            MediaTttSenderCoordinator(
+                mockChipbarCoordinator,
+                commandQueue,
+                context,
+                logger,
+                mediaTttFlags,
+                uiEventLogger,
+            )
+        underTest.start()
+        setCommandQueueCallback()
+
+        // WHEN there are two different media transfers with different IDs
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            MediaRoute2Info.Builder("route1", OTHER_DEVICE_NAME)
+                .addFeature("feature")
+                .setClientPackageName(PACKAGE_NAME)
+                .build(),
+            null,
+        )
+        commandQueueCallback.updateMediaTapToTransferSenderDisplay(
+            StatusBarManager.MEDIA_TRANSFER_SENDER_STATE_ALMOST_CLOSE_TO_END_CAST,
+            MediaRoute2Info.Builder("route2", OTHER_DEVICE_NAME)
+                .addFeature("feature")
+                .setClientPackageName(PACKAGE_NAME)
+                .build(),
+            null,
+        )
+
+        val listenerCaptor = argumentCaptor<TemporaryViewDisplayController.Listener>()
+        verify(mockChipbarCoordinator, atLeast(1)).registerListener(capture(listenerCaptor))
+
+        // THEN one of them is removed
+        listenerCaptor.value.onInfoPermanentlyRemoved("route1")
+
+        // THEN the media coordinator doesn't unregister the listener (since route2 is still active)
+        verify(mockChipbarCoordinator, never()).unregisterListener(listenerCaptor.value)
+    }
+
     private fun getChipbarView(): ViewGroup {
         val viewCaptor = ArgumentCaptor.forClass(View::class.java)
         verify(windowManager).addView(viewCaptor.capture(), any())
@@ -960,8 +1129,16 @@
             null
         )
     }
+
+    private fun setCommandQueueCallback() {
+        val callbackCaptor = argumentCaptor<CommandQueue.Callbacks>()
+        verify(commandQueue).addCallback(capture(callbackCaptor))
+        commandQueueCallback = callbackCaptor.value
+        reset(commandQueue)
+    }
 }
 
+private const val DEFAULT_ID = "defaultId"
 private const val APP_NAME = "Fake app name"
 private const val OTHER_DEVICE_NAME = "My Tablet"
 private const val BLANK_DEVICE_NAME = " "
@@ -969,13 +1146,13 @@
 private const val TIMEOUT = 10000
 
 private val routeInfo =
-    MediaRoute2Info.Builder("id", OTHER_DEVICE_NAME)
+    MediaRoute2Info.Builder(DEFAULT_ID, OTHER_DEVICE_NAME)
         .addFeature("feature")
         .setClientPackageName(PACKAGE_NAME)
         .build()
 
 private val routeInfoWithBlankDeviceName =
-    MediaRoute2Info.Builder("id", BLANK_DEVICE_NAME)
+    MediaRoute2Info.Builder(DEFAULT_ID, BLANK_DEVICE_NAME)
         .addFeature("feature")
         .setClientPackageName(PACKAGE_NAME)
         .build()
diff --git a/packages/SystemUI/tests/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayControllerTest.kt b/packages/SystemUI/tests/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayControllerTest.kt
index 99e2012..45f7df3 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayControllerTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/temporarydisplay/TemporaryViewDisplayControllerTest.kt
@@ -159,7 +159,7 @@
         underTest.displayView(getState())
         assertThat(fakeWakeLock.isHeld).isTrue()
 
-        underTest.removeView("id", "test reason")
+        underTest.removeView(DEFAULT_ID, "test reason")
 
         assertThat(fakeWakeLock.isHeld).isFalse()
     }
@@ -175,6 +175,8 @@
 
     @Test
     fun displayView_twiceWithDifferentIds_oldViewRemovedNewViewAdded() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "name",
@@ -199,10 +201,15 @@
         assertThat(windowParamsCaptor.allValues[0].title).isEqualTo("First Fake Window Title")
         assertThat(windowParamsCaptor.allValues[1].title).isEqualTo("Second Fake Window Title")
         verify(windowManager).removeView(viewCaptor.allValues[0])
+        // Since the controller is still storing the older view in case it'll get re-displayed
+        // later, the listener shouldn't be notified
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
     fun displayView_viewDoesNotDisappearsBeforeTimeout() {
+        val listener = registerListener()
+
         val state = getState()
         underTest.displayView(state)
         reset(windowManager)
@@ -210,10 +217,13 @@
         fakeClock.advanceTime(TIMEOUT_MS - 1)
 
         verify(windowManager, never()).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
     fun displayView_viewDisappearsAfterTimeout() {
+        val listener = registerListener()
+
         val state = getState()
         underTest.displayView(state)
         reset(windowManager)
@@ -221,10 +231,13 @@
         fakeClock.advanceTime(TIMEOUT_MS + 1)
 
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
     }
 
     @Test
     fun displayView_calledAgainBeforeTimeout_timeoutReset() {
+        val listener = registerListener()
+
         // First, display the view
         val state = getState()
         underTest.displayView(state)
@@ -239,10 +252,13 @@
 
         // Verify we didn't hide the view
         verify(windowManager, never()).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
     fun displayView_calledAgainBeforeTimeout_eventuallyTimesOut() {
+        val listener = registerListener()
+
         // First, display the view
         val state = getState()
         underTest.displayView(state)
@@ -255,6 +271,7 @@
         fakeClock.advanceTime(TIMEOUT_MS + 1)
 
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
     }
 
     @Test
@@ -271,25 +288,9 @@
     }
 
     @Test
-    fun viewUpdatedWithNewOnViewTimeoutRunnable_newRunnableUsed() {
-        var runnable1Run = false
-        underTest.displayView(ViewInfo(name = "name", id = "id1", windowTitle = "1")) {
-            runnable1Run = true
-        }
-
-        var runnable2Run = false
-        underTest.displayView(ViewInfo(name = "name", id = "id1", windowTitle = "1")) {
-            runnable2Run = true
-        }
-
-        fakeClock.advanceTime(TIMEOUT_MS + 1)
-
-        assertThat(runnable1Run).isFalse()
-        assertThat(runnable2Run).isTrue()
-    }
-
-    @Test
     fun multipleViewsWithDifferentIds_moreRecentReplacesOlder() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "name",
@@ -315,10 +316,16 @@
         assertThat(windowParamsCaptor.allValues[1].title).isEqualTo("Second Fake Window Title")
         verify(windowManager).removeView(viewCaptor.allValues[0])
         verify(configurationController, never()).removeCallback(any())
+
+        // Since the controller is still storing the older view in case it'll get re-displayed
+        // later, the listener shouldn't be notified
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
-    fun multipleViewsWithDifferentIds_recentActiveViewIsDisplayed() {
+    fun multipleViewsWithDifferentIds_newViewRemoved_previousViewIsDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(ViewInfo("First name", id = "id1"))
 
         verify(windowManager).addView(any(), any())
@@ -329,24 +336,35 @@
         verify(windowManager).removeView(any())
         verify(windowManager).addView(any(), any())
         reset(windowManager)
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
 
+        // WHEN the current view is removed
         underTest.removeView("id2", "test reason")
 
+        // THEN it's correctly removed
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly("id2")
+
+        // And the previous view is correctly added
         verify(windowManager).addView(any(), any())
         assertThat(underTest.mostRecentViewInfo?.id).isEqualTo("id1")
         assertThat(underTest.mostRecentViewInfo?.name).isEqualTo("First name")
 
+        // WHEN the previous view times out
         reset(windowManager)
         fakeClock.advanceTime(TIMEOUT_MS + 1)
 
+        // THEN it is also removed
         verify(windowManager).removeView(any())
         assertThat(underTest.activeViews.size).isEqualTo(0)
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).isEqualTo(listOf("id2", "id1"))
     }
 
     @Test
     fun multipleViewsWithDifferentIds_oldViewRemoved_recentViewIsDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(ViewInfo("First name", id = "id1"))
 
         verify(windowManager).addView(any(), any())
@@ -361,7 +379,8 @@
         // WHEN an old view is removed
         underTest.removeView("id1", "test reason")
 
-        // THEN we don't update anything
+        // THEN we don't update anything except the listener
+        assertThat(listener.permanentlyRemovedIds).containsExactly("id1")
         verify(windowManager, never()).removeView(any())
         assertThat(underTest.mostRecentViewInfo?.id).isEqualTo("id2")
         assertThat(underTest.mostRecentViewInfo?.name).isEqualTo("Second name")
@@ -372,10 +391,13 @@
         verify(windowManager).removeView(any())
         assertThat(underTest.activeViews.size).isEqualTo(0)
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).isEqualTo(listOf("id1", "id2"))
     }
 
     @Test
     fun multipleViewsWithDifferentIds_threeDifferentViews_recentActiveViewIsDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(ViewInfo("First name", id = "id1"))
         underTest.displayView(ViewInfo("Second name", id = "id2"))
         underTest.displayView(ViewInfo("Third name", id = "id3"))
@@ -387,6 +409,7 @@
         underTest.removeView("id3", "test reason")
 
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEqualTo(listOf("id3"))
         assertThat(underTest.mostRecentViewInfo?.id).isEqualTo("id2")
         assertThat(underTest.mostRecentViewInfo?.name).isEqualTo("Second name")
         verify(configurationController, never()).removeCallback(any())
@@ -395,6 +418,7 @@
         underTest.removeView("id2", "test reason")
 
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEqualTo(listOf("id3", "id2"))
         assertThat(underTest.mostRecentViewInfo?.id).isEqualTo("id1")
         assertThat(underTest.mostRecentViewInfo?.name).isEqualTo("First name")
         verify(configurationController, never()).removeCallback(any())
@@ -403,6 +427,7 @@
         fakeClock.advanceTime(TIMEOUT_MS + 1)
 
         verify(windowManager).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEqualTo(listOf("id3", "id2", "id1"))
         assertThat(underTest.activeViews.size).isEqualTo(0)
         verify(configurationController).removeCallback(any())
     }
@@ -438,6 +463,8 @@
 
     @Test
     fun multipleViews_mostRecentViewRemoved_otherViewsTimedOutAndNotDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(ViewInfo("First name", id = "id1", timeoutMs = 4000))
         fakeClock.advanceTime(1000)
         underTest.displayView(ViewInfo("Second name", id = "id2", timeoutMs = 4000))
@@ -451,10 +478,13 @@
         verify(windowManager, never()).addView(any(), any())
         assertThat(underTest.activeViews.size).isEqualTo(0)
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly("id1", "id2", "id3")
     }
 
     @Test
     fun multipleViews_mostRecentViewRemoved_viewWithShortTimeLeftNotDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(ViewInfo("First name", id = "id1", timeoutMs = 4000))
         fakeClock.advanceTime(1000)
         underTest.displayView(ViewInfo("Second name", id = "id2", timeoutMs = 2500))
@@ -467,10 +497,13 @@
         verify(windowManager, never()).addView(any(), any())
         assertThat(underTest.activeViews.size).isEqualTo(0)
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly("id1", "id2")
     }
 
     @Test
     fun lowerThenHigherPriority_higherReplacesLower() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "normal",
@@ -499,10 +532,15 @@
         verify(windowManager).addView(capture(viewCaptor), capture(windowParamsCaptor))
         assertThat(windowParamsCaptor.value.title).isEqualTo("Critical Window Title")
         verify(configurationController, never()).removeCallback(any())
+        // Since the controller is still storing the older view in case it'll get re-displayed
+        // later, the listener shouldn't be notified
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
     fun lowerThenHigherPriority_lowerPriorityRedisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "normal",
@@ -537,6 +575,7 @@
 
         // THEN the normal view is re-displayed
         verify(windowManager).removeView(viewCaptor.allValues[1])
+        assertThat(listener.permanentlyRemovedIds).containsExactly("critical")
         verify(windowManager).addView(any(), capture(windowParamsCaptor))
         assertThat(windowParamsCaptor.value.title).isEqualTo("Normal Window Title")
         verify(configurationController, never()).removeCallback(any())
@@ -544,6 +583,8 @@
 
     @Test
     fun lowerThenHigherPriority_lowerPriorityNotRedisplayedBecauseTimedOut() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "normal",
@@ -573,6 +614,7 @@
         verify(windowManager, never()).addView(any(), any())
         assertThat(underTest.activeViews).isEmpty()
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly("critical", "normal")
     }
 
     @Test
@@ -609,6 +651,8 @@
 
     @Test
     fun higherThenLowerPriority_lowerEventuallyDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "critical",
@@ -644,6 +688,7 @@
 
         // THEN the second normal view is displayed
         verify(windowManager).removeView(viewCaptor.value)
+        assertThat(listener.permanentlyRemovedIds).containsExactly("critical")
         verify(windowManager).addView(capture(viewCaptor), capture(windowParamsCaptor))
         assertThat(windowParamsCaptor.value.title).isEqualTo("Normal Window Title")
         assertThat(underTest.activeViews.size).isEqualTo(1)
@@ -652,6 +697,8 @@
 
     @Test
     fun higherThenLowerPriority_lowerNotDisplayedBecauseTimedOut() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "critical",
@@ -691,10 +738,13 @@
         verify(windowManager, never()).addView(any(), any())
         assertThat(underTest.activeViews).isEmpty()
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly("critical", "normal")
     }
 
     @Test
     fun criticalThenNewCritical_newCriticalDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "critical 1",
@@ -724,10 +774,15 @@
         assertThat(windowParamsCaptor.value.title).isEqualTo("Critical Window Title 2")
         assertThat(underTest.activeViews.size).isEqualTo(2)
         verify(configurationController, never()).removeCallback(any())
+        // Since the controller is still storing the older view in case it'll get re-displayed
+        // later, the listener shouldn't be notified
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
     fun normalThenNewNormal_newNormalDisplayed() {
+        val listener = registerListener()
+
         underTest.displayView(
             ViewInfo(
                 name = "normal 1",
@@ -757,6 +812,9 @@
         assertThat(windowParamsCaptor.value.title).isEqualTo("Normal Window Title 2")
         assertThat(underTest.activeViews.size).isEqualTo(2)
         verify(configurationController, never()).removeCallback(any())
+        // Since the controller is still storing the older view in case it'll get re-displayed
+        // later, the listener shouldn't be notified
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
     }
 
     @Test
@@ -957,25 +1015,103 @@
     }
 
     @Test
-    fun removeView_viewRemovedAndRemovalLogged() {
+    fun removeView_viewRemovedAndRemovalLoggedAndListenerNotified() {
+        val listener = registerListener()
+
         // First, add the view
         underTest.displayView(getState())
 
         // Then, remove it
         val reason = "test reason"
-        val deviceId = "id"
-        underTest.removeView(deviceId, reason)
+        underTest.removeView(DEFAULT_ID, reason)
 
         verify(windowManager).removeView(any())
-        verify(logger).logViewRemoval(deviceId, reason)
+        verify(logger).logViewRemoval(DEFAULT_ID, reason)
         verify(configurationController).removeCallback(any())
+        assertThat(listener.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
     }
 
     @Test
-    fun removeView_noAdd_viewNotRemoved() {
+    fun removeView_noAdd_viewNotRemovedAndListenerNotNotified() {
+        val listener = registerListener()
+
         underTest.removeView("id", "reason")
 
         verify(windowManager, never()).removeView(any())
+        assertThat(listener.permanentlyRemovedIds).isEmpty()
+    }
+
+    @Test
+    fun listenerRegistered_notifiedOnRemoval() {
+        val listener = registerListener()
+        underTest.displayView(getState())
+
+        underTest.removeView(DEFAULT_ID, "reason")
+
+        assertThat(listener.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
+    }
+
+    @Test
+    fun listenerRegistered_notifiedOnTimedOutEvenWhenNotDisplayed() {
+        val listener = registerListener()
+        underTest.displayView(
+            ViewInfo(
+                id = "id1",
+                name = "name1",
+                timeoutMs = 3000,
+            ),
+        )
+
+        // Display a second view
+        underTest.displayView(
+            ViewInfo(
+                id = "id2",
+                name = "name2",
+                timeoutMs = 2500,
+            ),
+        )
+
+        // WHEN the second view times out
+        fakeClock.advanceTime(2501)
+
+        // THEN the listener is notified of both IDs, since id2 timed out and id1 doesn't have
+        // enough time left to be redisplayed
+        assertThat(listener.permanentlyRemovedIds).containsExactly("id1", "id2")
+    }
+
+    @Test
+    fun multipleListeners_allNotified() {
+        val listener1 = registerListener()
+        val listener2 = registerListener()
+        val listener3 = registerListener()
+
+        underTest.displayView(getState())
+
+        underTest.removeView(DEFAULT_ID, "reason")
+
+        assertThat(listener1.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
+        assertThat(listener2.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
+        assertThat(listener3.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
+    }
+
+    @Test
+    fun sameListenerRegisteredMultipleTimes_onlyNotifiedOnce() {
+        val listener = registerListener()
+        underTest.registerListener(listener)
+        underTest.registerListener(listener)
+
+        underTest.displayView(getState())
+
+        underTest.removeView(DEFAULT_ID, "reason")
+
+        assertThat(listener.permanentlyRemovedIds).hasSize(1)
+        assertThat(listener.permanentlyRemovedIds).containsExactly(DEFAULT_ID)
+    }
+
+    private fun registerListener(): Listener {
+        return Listener().also {
+            underTest.registerListener(it)
+        }
     }
 
     private fun getState(name: String = "name") = ViewInfo(name)
@@ -1030,9 +1166,17 @@
         override val windowTitle: String = "Window Title",
         override val wakeReason: String = "WAKE_REASON",
         override val timeoutMs: Int = TIMEOUT_MS.toInt(),
-        override val id: String = "id",
+        override val id: String = DEFAULT_ID,
         override val priority: ViewPriority = ViewPriority.NORMAL,
     ) : TemporaryViewInfo()
+
+    inner class Listener : TemporaryViewDisplayController.Listener {
+        val permanentlyRemovedIds = mutableListOf<String>()
+        override fun onInfoPermanentlyRemoved(id: String) {
+            permanentlyRemovedIds.add(id)
+        }
+    }
 }
 
 private const val TIMEOUT_MS = 10000L
+private const val DEFAULT_ID = "defaultId"