Reland "[StartSurface] Switch to normal tab model on resume to V2 start surface"

This is a reland of 9b955d94

Original change's description:
> [StartSurface] Switch to normal tab model on resume to V2 start surface
> 
> This CL also solves the scroll issue of the incognito description.
> 
> Screen records:
> Resume:
> https://drive.google.com/file/d/1jPFCAEwTDzI4PO-Ef-HdvRV6KeZoW4fD/view?usp=sharing
> 
> Scroll:
> https://drive.google.com/file/d/1C2lFMBKmdTaipWcHBG9mAYCJNuhoiYK_/view?usp=sharing
> 
> Bug: 1093506
> Change-Id: I5d7365daa530b23f897a19665076cbc32238224f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243334
> Commit-Queue: Ganggui Tang <gogerald@chromium.org>
> Auto-Submit: Ganggui Tang <gogerald@chromium.org>
> Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
> Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#779878}

Bug: 1093506
Change-Id: Ie49546277d347eea6682064a41a859f52b882a7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2254578
Auto-Submit: Ganggui Tang <gogerald@chromium.org>
Commit-Queue: Yusuf Ozuysal <yusufo@chromium.org>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#780386}

chrome/android/features/start_surface/internal/java/src/org/chromium/chrome/features/start_surface/StartSurfaceMediator.java

@@ -8,6 +8,7 @@ import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_FAKE_S
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_INITIALIZED;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_VISIBLE;
+import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_SURFACE_BODY_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_TAB_CAROUSEL_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_VOICE_RECOGNITION_BUTTON_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.MORE_TABS_CLICK_LISTENER;
@@ -748,11 +749,13 @@ class StartSurfaceMediator
             mPropertyModel.set(IS_INCOGNITO_DESCRIPTION_INITIALIZED, true);
         }
         mPropertyModel.set(IS_INCOGNITO_DESCRIPTION_VISIBLE, isVisible);
+        mPropertyModel.set(IS_SURFACE_BODY_VISIBLE, !isVisible);
         if (mSecondaryTasksSurfacePropertyModel != null) {
             if (!mSecondaryTasksSurfacePropertyModel.get(IS_INCOGNITO_DESCRIPTION_INITIALIZED)) {
                 mSecondaryTasksSurfacePropertyModel.set(IS_INCOGNITO_DESCRIPTION_INITIALIZED, true);
             }
             mSecondaryTasksSurfacePropertyModel.set(IS_INCOGNITO_DESCRIPTION_VISIBLE, isVisible);
+            mSecondaryTasksSurfacePropertyModel.set(IS_SURFACE_BODY_VISIBLE, !isVisible);
         }
     }
 

chrome/android/features/start_surface/internal/javatests/src/org/chromium/chrome/features/start_surface/StartSurfaceTest.java

@@ -38,6 +38,7 @@ import static org.chromium.chrome.test.util.ViewUtils.onViewWaiting;
 import static org.chromium.chrome.test.util.ViewUtils.waitForView;
 
 import android.content.Intent;
+import android.os.Build;
 import android.support.test.InstrumentationRegistry;
 import android.view.KeyEvent;
 import android.view.ViewGroup;
@@ -639,6 +640,10 @@ public class StartSurfaceTest {
             TestThreadUtils.runOnUiThreadBlocking(() -> {
                 mActivityTestRule.getActivity().getTabModelSelector().selectModel(true);
             });
+
+            // TODO(crbug.com/1097001): remove after fixing the default focus issue, which might
+            // relate to crbug.com/1076274 above since it doesn't exist for the other combinations.
+            assumeTrue(Build.VERSION.SDK_INT >= Build.VERSION_CODES.P);
         } else {
             onView(withId(R.id.incognito_switch)).perform(click());
         }

chrome/android/features/start_surface/internal/junit/src/org/chromium/chrome/features/start_surface/StartSurfaceMediatorUnitTest.java

@@ -21,6 +21,7 @@ import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_FAKE_S
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_INITIALIZED;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_VISIBLE;
+import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_SURFACE_BODY_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_TAB_CAROUSEL_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_VOICE_RECOGNITION_BUTTON_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.MV_TILES_CONTAINER_TOP_MARGIN;
@@ -1078,16 +1079,19 @@ public class StartSurfaceMediatorUnitTest {
 
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_INITIALIZED), equalTo(false));
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_VISIBLE), equalTo(false));
+        assertThat(mPropertyModel.get(IS_SURFACE_BODY_VISIBLE), equalTo(false));
         doReturn(0).when(mIncognitoTabModel).getCount();
         mTabModelSelectorObserverCaptor.getValue().onTabModelSelected(
                 mIncognitoTabModel, mNormalTabModel);
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_INITIALIZED), equalTo(true));
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_VISIBLE), equalTo(true));
+        assertThat(mPropertyModel.get(IS_SURFACE_BODY_VISIBLE), equalTo(false));
 
         mTabModelSelectorObserverCaptor.getValue().onTabModelSelected(
                 mNormalTabModel, mIncognitoTabModel);
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_INITIALIZED), equalTo(true));
         assertThat(mPropertyModel.get(IS_INCOGNITO_DESCRIPTION_VISIBLE), equalTo(false));
+        assertThat(mPropertyModel.get(IS_SURFACE_BODY_VISIBLE), equalTo(true));
 
         mediator.hideOverview(true);
     }

chrome/android/features/tab_ui/BUILD.gn

@@ -55,6 +55,7 @@ android_resources("java_resources") {
     "java/res/layout/bottom_tab_strip_toolbar.xml",
     "java/res/layout/closable_tab_grid_card_item.xml",
     "java/res/layout/closable_tab_list_card_item.xml",
+    "java/res/layout/incognito_description_container_layout.xml",
     "java/res/layout/iph_drag_and_drop_dialog_layout.xml",
     "java/res/layout/new_tab_tile_card_item.xml",
     "java/res/layout/selectable_tab_grid_card_item.xml",

chrome/android/features/tab_ui/java/res/layout/incognito_description_container_layout.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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. -->
+
+<androidx.core.widget.NestedScrollView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+    <include layout="@layout/incognito_description_layout" />
+</androidx.core.widget.NestedScrollView>

chrome/android/features/tab_ui/java/res/layout/tasks_view_layout.xml

@@ -16,12 +16,6 @@
         android:layout_height="wrap_content"
         app:elevation="0dp">
         <include layout="@layout/fake_search_box_layout"/>
-        <ViewStub
-            android:id="@+id/incognito_description_layout_stub"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:layout="@layout/incognito_description_layout"
-            app:layout_scrollFlags="scroll" />
         <HorizontalScrollView android:id="@+id/mv_tiles_container"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
@@ -78,9 +72,21 @@
             android:visibility="gone"
             app:layout_scrollFlags="scroll"/>
     </com.google.android.material.appbar.AppBarLayout>
+
+    <!-- This incognito_description_container_layout_stub and the below tasks_surface_body
+         should be mutually exclusive, otherwise they will overlap each other. -->
+    <ViewStub
+        android:id="@+id/incognito_description_container_layout_stub"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout="@layout/incognito_description_container_layout"
+        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
+
+    <!-- Note that this FrameLayout can not be added to NestedScrollView, otherwise the
+         RecyclerView added to this FrameLayout won't recycle. -->
     <FrameLayout
         android:id="@+id/tasks_surface_body"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
+        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
 </org.chromium.chrome.browser.tasks.TasksView>

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/TasksSurfaceMediator.java

@@ -14,6 +14,7 @@ import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.INCOGNITO
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.INCOGNITO_COOKIE_CONTROLS_TOGGLE_ENFORCEMENT;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.INCOGNITO_LEARN_MORE_CLICK_LISTENER;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_FAKE_SEARCH_BOX_VISIBLE;
+import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_SURFACE_BODY_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_TAB_CAROUSEL_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_VOICE_RECOGNITION_BUTTON_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.VOICE_SEARCH_BUTTON_CLICK_LISTENER;
@@ -52,6 +53,9 @@ class TasksSurfaceMediator {
         // Set Incognito Cookie Controls functionality
         mIncognitoCookieControlsManager = incognitoCookieControlsManager;
         mModel.set(INCOGNITO_COOKIE_CONTROLS_MANAGER, mIncognitoCookieControlsManager);
+
+        // Set the initial state.
+        mModel.set(IS_SURFACE_BODY_VISIBLE, true);
     }
 
     public void initWithNative(FakeboxDelegate fakeboxDelegate) {

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/TasksSurfaceProperties.java

@@ -27,6 +27,8 @@ public class TasksSurfaceProperties {
             new PropertyModel.WritableBooleanPropertyKey();
     public static final PropertyModel.WritableBooleanPropertyKey IS_INCOGNITO_DESCRIPTION_VISIBLE =
             new PropertyModel.WritableBooleanPropertyKey();
+    public static final PropertyModel.WritableBooleanPropertyKey IS_SURFACE_BODY_VISIBLE =
+            new PropertyModel.WritableBooleanPropertyKey();
     public static final PropertyModel.WritableBooleanPropertyKey IS_TAB_CAROUSEL_VISIBLE =
             new PropertyModel.WritableBooleanPropertyKey();
     public static final PropertyModel
@@ -74,7 +76,7 @@ public class TasksSurfaceProperties {
             new PropertyModel.WritableIntPropertyKey();
     public static final PropertyKey[] ALL_KEYS = new PropertyKey[] {IS_FAKE_SEARCH_BOX_VISIBLE,
             IS_INCOGNITO, IS_INCOGNITO_DESCRIPTION_INITIALIZED, IS_INCOGNITO_DESCRIPTION_VISIBLE,
-            IS_TAB_CAROUSEL_VISIBLE, IS_VOICE_RECOGNITION_BUTTON_VISIBLE,
+            IS_SURFACE_BODY_VISIBLE, IS_TAB_CAROUSEL_VISIBLE, IS_VOICE_RECOGNITION_BUTTON_VISIBLE,
             INCOGNITO_COOKIE_CONTROLS_CARD_VISIBILITY,
             INCOGNITO_COOKIE_CONTROLS_ICON_CLICK_LISTENER, INCOGNITO_COOKIE_CONTROLS_TOGGLE_CHECKED,
             INCOGNITO_COOKIE_CONTROLS_TOGGLE_CHECKED_LISTENER,

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/TasksView.java

@@ -136,6 +136,14 @@ class TasksView extends CoordinatorLayoutForPointer {
         return findViewById(R.id.tasks_surface_body);
     }
 
+    /**
+     * Set the visibility of the tasks surface body.
+     * @param isVisible Whether it's visible.
+     */
+    void setSurfaceBodyVisibility(boolean isVisible) {
+        getBodyViewContainer().setVisibility(isVisible ? View.VISIBLE : View.GONE);
+    }
+
     /**
      * Set the visibility of the tab carousel.
      * @param isVisible Whether it's visible.
@@ -190,8 +198,11 @@ class TasksView extends CoordinatorLayoutForPointer {
      */
     void initializeIncognitoDescriptionView() {
         assert mIncognitoDescriptionView == null;
-        ViewStub stub = (ViewStub) findViewById(R.id.incognito_description_layout_stub);
-        mIncognitoDescriptionView = (IncognitoDescriptionView) stub.inflate();
+        ViewStub containerStub =
+                (ViewStub) findViewById(R.id.incognito_description_container_layout_stub);
+        View containerView = containerStub.inflate();
+        mIncognitoDescriptionView = (IncognitoDescriptionView) containerView.findViewById(
+                R.id.new_tab_incognito_container);
         if (mIncognitoDescriptionLearnMoreListener != null) {
             setIncognitoDescriptionLearnMoreClickListener(mIncognitoDescriptionLearnMoreListener);
         }

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/TasksViewBinder.java

@@ -17,6 +17,7 @@ import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_FAKE_S
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_INITIALIZED;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_VISIBLE;
+import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_SURFACE_BODY_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_TAB_CAROUSEL_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_VOICE_RECOGNITION_BUTTON_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.MORE_TABS_CLICK_LISTENER;
@@ -74,6 +75,8 @@ class TasksViewBinder {
                 model.get(INCOGNITO_COOKIE_CONTROLS_MANAGER).updateIfNecessary();
             }
             view.setIncognitoDescriptionVisibility(isVisible);
+        } else if (propertyKey == IS_SURFACE_BODY_VISIBLE) {
+            view.setSurfaceBodyVisibility(model.get(IS_SURFACE_BODY_VISIBLE));
         } else if (propertyKey == IS_TAB_CAROUSEL_VISIBLE) {
             view.setTabCarouselVisibility(model.get(IS_TAB_CAROUSEL_VISIBLE));
         } else if (propertyKey == IS_VOICE_RECOGNITION_BUTTON_VISIBLE) {

chrome/android/features/tab_ui/javatests/src/org/chromium/chrome/browser/tasks/TasksViewBinderTest.java

@@ -222,12 +222,12 @@ public class TasksViewBinderTest extends DummyUiActivityTestCase {
     @Test
     @SmallTest
     public void testSetIncognitoDescriptionVisibilityAndClickListener() {
-        assertFalse(isViewVisible(R.id.incognito_description_layout_stub));
+        assertFalse(isViewVisible(R.id.incognito_description_container_layout_stub));
 
         TestThreadUtils.runOnUiThreadBlocking(() -> {
             mTasksViewPropertyModel.set(INCOGNITO_LEARN_MORE_CLICK_LISTENER, mViewOnClickListener);
         });
-        assertFalse(isViewVisible(R.id.incognito_description_layout_stub));
+        assertFalse(isViewVisible(R.id.incognito_description_container_layout_stub));
 
         TestThreadUtils.runOnUiThreadBlocking(() -> {
             mTasksViewPropertyModel.set(INCOGNITO_COOKIE_CONTROLS_MANAGER, mCookieControlsManager);

chrome/android/features/tab_ui/junit/src/org/chromium/chrome/browser/tasks/TasksSurfaceMediatorUnitTest.java

@@ -21,6 +21,7 @@ import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.INCOGNITO
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_FAKE_SEARCH_BOX_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_INITIALIZED;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_INCOGNITO_DESCRIPTION_VISIBLE;
+import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_SURFACE_BODY_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_TAB_CAROUSEL_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.IS_VOICE_RECOGNITION_BUTTON_VISIBLE;
 import static org.chromium.chrome.browser.tasks.TasksSurfaceProperties.VOICE_SEARCH_BUTTON_CLICK_LISTENER;
@@ -99,6 +100,7 @@ public class TasksSurfaceMediatorUnitTest {
                         mVoiceSearchButtonClickListenerCaptor.capture());
         verify(mPropertyModel).set(eq(IS_FAKE_SEARCH_BOX_VISIBLE), eq(true));
         verify(mPropertyModel).set(eq(IS_VOICE_RECOGNITION_BUTTON_VISIBLE), eq(false));
+        verify(mPropertyModel).set(eq(IS_SURFACE_BODY_VISIBLE), eq(true));
         verify(mPropertyModel)
                 .set(eq(INCOGNITO_COOKIE_CONTROLS_MANAGER), mCookieControlsManagerCaptor.capture());
         verify(mPropertyModel)

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

@@ -906,6 +906,12 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
     public void onResumeWithNative() {
         super.onResumeWithNative();
 
+        // Switch to non incognito tab model to show the non incognito start surface if needed.
+        if (StartSurfaceConfiguration.isStartSurfaceStackTabSwitcherEnabled() && isWarmOnResume()
+                && shouldShowTabSwitcherOnStart() && mTabModelSelectorImpl.isIncognitoSelected()) {
+            mTabModelSelectorImpl.selectModel(false);
+        }
+
         if (IncognitoUtils.shouldDestroyIncognitoProfileOnStartup(
                     getTabModelSelector().getCurrentModel().isIncognito())) {
             Profile.getLastUsedRegularProfile().getOffTheRecordProfile().destroyWhenAppropriate();

chrome/android/javatests/src/org/chromium/chrome/browser/tasks/ReturnToChromeTest.java

@@ -7,6 +7,7 @@ package org.chromium.chrome.browser.tasks;
 import static com.google.common.truth.Truth.assertThat;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assume.assumeFalse;
 import static org.junit.Assume.assumeTrue;
 
 import static org.chromium.chrome.browser.tasks.ReturnToChromeExperimentsUtil.TAB_SWITCHER_ON_RETURN_MS_PARAM;
@@ -54,7 +55,9 @@ import org.chromium.chrome.features.start_surface.InstantStartTest;
 import org.chromium.chrome.features.start_surface.StartSurfaceConfiguration;
 import org.chromium.chrome.test.ChromeJUnit4RunnerDelegate;
 import org.chromium.chrome.test.ChromeTabbedActivityTestRule;
+import org.chromium.chrome.test.util.ApplicationTestUtils;
 import org.chromium.chrome.test.util.ChromeRenderTestRule;
+import org.chromium.chrome.test.util.ChromeTabUtils;
 import org.chromium.chrome.test.util.browser.Features;
 import org.chromium.chrome.test.util.browser.Features.EnableFeatures;
 import org.chromium.components.embedder_support.util.UrlConstants;
@@ -266,6 +269,79 @@ public class ReturnToChromeTest {
         }
     }
 
+    /**
+     * Test that overview mode is triggered in Single-pane stack tab switcher variation in non
+     * incognito mode when resuming from incognito mode.
+     */
+    @Test
+    @SmallTest
+    @Feature({"ReturnToChrome"})
+    // clang-format off
+    @CommandLineFlags.Add({BASE_PARAMS + "/" + TAB_SWITCHER_ON_RETURN_MS_PARAM + "/0"
+            + "/start_surface_variation/single/show_last_active_tab_only/true"
+            + "/show_stack_tab_switcher/true/open_ntp_instead_of_start/true"})
+    @DisableIf.Device(type = {UiDisableIf.TABLET}) // See https://crbug.com/1081754.
+    public void testTabSwitcherModeTriggeredWithinThreshold_WarmStart_FromIncognito_V2() throws Exception {
+        // clang-format on
+
+        // TODO(crbug.com/1093506): Remove it when instant start supports 'show_stack_tab_switcher =
+        // true'.
+        assumeFalse(CachedFeatureFlags.isEnabled(ChromeFeatureList.INSTANT_START));
+
+        testTabSwitcherModeTriggeredBeyondThreshold();
+
+        ChromeTabUtils.newTabFromMenu(InstrumentationRegistry.getInstrumentation(),
+                mActivityTestRule.getActivity(), true, true);
+        Assert.assertTrue(
+                mActivityTestRule.getActivity().getTabModelSelector().isIncognitoSelected());
+        assertEquals(3, mActivityTestRule.getActivity().getTabModelSelector().getTotalTabCount());
+
+        // Trigger hide and resume.
+        ApplicationTestUtils.fireHomeScreenIntent(InstrumentationRegistry.getTargetContext());
+        mActivityTestRule.startMainActivityFromLauncher();
+
+        Assert.assertFalse(
+                mActivityTestRule.getActivity().getTabModelSelector().isIncognitoSelected());
+        assertEquals(3, mActivityTestRule.getActivity().getTabModelSelector().getTotalTabCount());
+        Assert.assertTrue(mActivityTestRule.getActivity().getLayoutManager().overviewVisible());
+    }
+
+    /**
+     * Test that overview mode is triggered in Single-pane non stack tab switcher variation in
+     * incognito mode when resuming from incognito mode.
+     */
+    @Test
+    @SmallTest
+    @Feature({"ReturnToChrome"})
+    // clang-format off
+    @CommandLineFlags.Add({BASE_PARAMS + "/" + TAB_SWITCHER_ON_RETURN_MS_PARAM + "/0"
+            + "/start_surface_variation/single/"
+            + "show_last_active_tab_only/true/open_ntp_instead_of_start/true"})
+    @DisableIf.Device(type = {UiDisableIf.TABLET}) // See https://crbug.com/1081754.
+    public void testTabSwitcherModeTriggeredWithinThreshold_WarmStart_FromIncognito_NON_V2() throws Exception {
+        // clang-format on
+
+        // TODO(crbug.com/1095637): Make it work for instant start.
+        assumeFalse(CachedFeatureFlags.isEnabled(ChromeFeatureList.INSTANT_START));
+
+        testTabSwitcherModeTriggeredBeyondThreshold();
+
+        ChromeTabUtils.newTabFromMenu(InstrumentationRegistry.getInstrumentation(),
+                mActivityTestRule.getActivity(), true, true);
+        Assert.assertTrue(
+                mActivityTestRule.getActivity().getTabModelSelector().isIncognitoSelected());
+        assertEquals(3, mActivityTestRule.getActivity().getTabModelSelector().getTotalTabCount());
+
+        // Trigger hide and resume.
+        ApplicationTestUtils.fireHomeScreenIntent(InstrumentationRegistry.getTargetContext());
+        mActivityTestRule.startMainActivityFromLauncher();
+
+        Assert.assertTrue(
+                mActivityTestRule.getActivity().getTabModelSelector().isIncognitoSelected());
+        assertEquals(3, mActivityTestRule.getActivity().getTabModelSelector().getTotalTabCount());
+        Assert.assertTrue(mActivityTestRule.getActivity().getLayoutManager().overviewVisible());
+    }
+
     /**
      * Test that overview mode is triggered if the delay is shorter than the interval between
      * stop and start.