Make ViewsTestBase::task_environment_ private.

This code jumped through a lot of complex hoops to allow subclasses to
provide a TestEnvironment of their own.  But no subclasses actually
want a test environment with a different lifetime than the parent's.
So just allow people to pass in a TestEnvironment instance instead.

This, coupled with providing an accessor for calling methods, allows
making the TaskEnvironment private instead of protected.

Bug: none
Change-Id: I923f5b232eb8fc01cc445e4d51cf45707d167ae7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2126093
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754560}

chrome/browser/chromeos/child_accounts/time_limits/app_activity_registry_unittest.cc

@@ -69,9 +69,7 @@ class AppStateObserverMock : public AppActivityRegistry::AppStateObserver {
 
 class AppActivityRegistryTest : public ChromeViewsTestBase {
  protected:
-  AppActivityRegistryTest()
-      : ChromeViewsTestBase(
-            base::test::TaskEnvironment::TimeSource::MOCK_TIME) {}
+  AppActivityRegistryTest() = default;
   AppActivityRegistryTest(const AppActivityRegistryTest&) = delete;
   AppActivityRegistryTest& operator=(const AppActivityRegistryTest&) = delete;
   ~AppActivityRegistryTest() override = default;
@@ -98,7 +96,6 @@ class AppActivityRegistryTest : public ChromeViewsTestBase {
     return *registry_test_;
   }
 
-  base::test::TaskEnvironment& task_environment() { return task_environment_; }
   AppTimeNotificationDelegateMock& notification_delegate_mock() {
     return notification_delegate_mock_;
   }
@@ -152,7 +149,7 @@ void AppActivityRegistryTest::SetAppLimit(
     const AppId& app_id,
     const base::Optional<AppLimit>& app_limit) {
   registry().SetAppLimit(app_id, app_limit);
-  task_environment_.RunUntilIdle();
+  task_environment()->RunUntilIdle();
 }
 
 void AppActivityRegistryTest::ReInitializeRegistry() {
@@ -168,7 +165,7 @@ void AppActivityRegistryTest::CreateAppActivityForApp(
     base::TimeDelta activity_length) {
   auto* app_window = CreateWindowForApp(app_id);
   registry().OnAppActive(app_id, app_window, base::Time::Now());
-  task_environment().FastForwardBy(activity_length);
+  task_environment()->FastForwardBy(activity_length);
   registry().OnAppInactive(app_id, app_window, base::Time::Now());
 }
 
@@ -178,11 +175,11 @@ TEST_F(AppActivityRegistryTest, RunningActiveTimeCheck) {
   base::Time app1_start_time = base::Time::Now();
   base::TimeDelta active_time = base::TimeDelta::FromMinutes(5);
   registry().OnAppActive(kApp1, app1_window, app1_start_time);
-  task_environment().FastForwardBy(active_time / 2);
+  task_environment()->FastForwardBy(active_time / 2);
   EXPECT_EQ(active_time / 2, registry().GetActiveTime(kApp1));
   EXPECT_TRUE(registry().IsAppActive(kApp1));
 
-  task_environment().FastForwardBy(active_time / 2);
+  task_environment()->FastForwardBy(active_time / 2);
   base::Time app1_end_time = base::Time::Now();
   registry().OnAppInactive(kApp1, app1_window, app1_end_time);
   EXPECT_EQ(active_time, registry().GetActiveTime(kApp1));
@@ -196,14 +193,14 @@ TEST_F(AppActivityRegistryTest, MultipleWindowSameApp) {
   base::TimeDelta app2_active_time = base::TimeDelta::FromMinutes(5);
 
   registry().OnAppActive(kApp2, app2_window1, base::Time::Now());
-  task_environment().FastForwardBy(app2_active_time / 2);
+  task_environment()->FastForwardBy(app2_active_time / 2);
 
   registry().OnAppActive(kApp2, app2_window2, base::Time::Now());
   registry().OnAppInactive(kApp2, app2_window1, base::Time::Now());
   registry().OnAppInactive(kApp2, app2_window1, base::Time::Now());
   EXPECT_TRUE(registry().IsAppActive(kApp2));
 
-  task_environment().FastForwardBy(app2_active_time / 2);
+  task_environment()->FastForwardBy(app2_active_time / 2);
 
   // Repeated calls to OnAppInactive shouldn't affect the time calculation.
   registry().OnAppInactive(kApp2, app2_window1, base::Time::Now());
@@ -218,14 +215,14 @@ TEST_F(AppActivityRegistryTest, MultipleWindowSameApp) {
   base::TimeDelta app2_inactive_time = base::TimeDelta::FromMinutes(1);
 
   registry().OnAppActive(kApp2, app2_window1, base::Time::Now());
-  task_environment().FastForwardBy(app2_active_time / 2);
+  task_environment()->FastForwardBy(app2_active_time / 2);
 
   registry().OnAppInactive(kApp2, app2_window1, base::Time::Now());
-  task_environment().FastForwardBy(app2_inactive_time);
+  task_environment()->FastForwardBy(app2_inactive_time);
   EXPECT_FALSE(registry().IsAppActive(kApp2));
 
   registry().OnAppActive(kApp2, app2_window2, base::Time::Now());
-  task_environment().FastForwardBy(app2_active_time / 2);
+  task_environment()->FastForwardBy(app2_active_time / 2);
 
   registry().OnAppInactive(kApp2, app2_window1, base::Time::Now());
   EXPECT_TRUE(registry().IsAppActive(kApp2));
@@ -256,7 +253,7 @@ TEST_F(AppActivityRegistryTest, AppTimeLimitReachedActiveApp) {
       ShowAppTimeLimitNotification(
           kApp1, testing::_, chromeos::app_time::AppNotification::kFiveMinutes))
       .Times(1);
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(5));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(5));
   EXPECT_EQ(base::TimeDelta::FromMinutes(5), registry().GetActiveTime(kApp1));
   EXPECT_TRUE(registry().IsAppActive(kApp1));
 
@@ -266,7 +263,7 @@ TEST_F(AppActivityRegistryTest, AppTimeLimitReachedActiveApp) {
       ShowAppTimeLimitNotification(
           kApp1, testing::_, chromeos::app_time::AppNotification::kOneMinute))
       .Times(1);
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(4));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(4));
   EXPECT_EQ(base::TimeDelta::FromMinutes(9), registry().GetActiveTime(kApp1));
 
   // Expect time limit reached notification.
@@ -275,7 +272,7 @@ TEST_F(AppActivityRegistryTest, AppTimeLimitReachedActiveApp) {
                   kApp1, testing::_,
                   chromeos::app_time::AppNotification::kTimeLimitReached))
       .Times(1);
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(1));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(1));
   EXPECT_EQ(base::TimeDelta::FromMinutes(10), registry().GetActiveTime(kApp1));
 
   EXPECT_EQ(registry().GetAppState(kApp1), AppState::kLimitReached);
@@ -294,7 +291,7 @@ TEST_F(AppActivityRegistryTest, SkippedFiveMinuteNotification) {
   base::TimeDelta active_time = base::TimeDelta::FromMinutes(10);
   registry().OnAppActive(kApp1, app1_window, start);
 
-  task_environment().FastForwardBy(active_time);
+  task_environment()->FastForwardBy(active_time);
 
   const AppLimit new_limit(AppRestriction::kTimeLimit,
                            base::TimeDelta::FromMinutes(14),
@@ -307,7 +304,7 @@ TEST_F(AppActivityRegistryTest, SkippedFiveMinuteNotification) {
       ShowAppTimeLimitNotification(
           kApp1, testing::_, chromeos::app_time::AppNotification::kOneMinute))
       .Times(1);
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(3));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(3));
 }
 
 TEST_F(AppActivityRegistryTest, SkippedAllNotifications) {
@@ -323,7 +320,7 @@ TEST_F(AppActivityRegistryTest, SkippedAllNotifications) {
   base::TimeDelta active_time = base::TimeDelta::FromMinutes(10);
   registry().OnAppActive(kApp1, app1_window, start);
 
-  task_environment().FastForwardBy(active_time);
+  task_environment()->FastForwardBy(active_time);
 
   // Notice that the 5 minute and 1 minute notifications are jumped.
   const AppLimit new_limit(AppRestriction::kTimeLimit,
@@ -347,7 +344,7 @@ TEST_F(AppActivityRegistryTest, BlockedAppSetAvailable) {
   // There are going to be a bunch of mock notification calls for kFiveMinutes,
   // kOneMinute, and kTimeLimitReached. They have already been tested in the
   // other tests. Let's igonre them.
-  task_environment().FastForwardBy(kTenMinutes);
+  task_environment()->FastForwardBy(kTenMinutes);
 
   EXPECT_EQ(registry().GetAppState(kApp1), AppState::kLimitReached);
 
@@ -374,7 +371,7 @@ TEST_F(AppActivityRegistryTest, ResetTimeReached) {
   registry().OnAppActive(kApp1, app1_window, start);
   registry().OnAppActive(kApp2, app2_window, start);
 
-  task_environment().FastForwardBy(kTenMinutes);
+  task_environment()->FastForwardBy(kTenMinutes);
 
   // App 1's time limit has been reached.
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kApp1));
@@ -394,7 +391,7 @@ TEST_F(AppActivityRegistryTest, ResetTimeReached) {
   // Now make sure that the timers have been scheduled appropriately.
   registry().OnAppActive(kApp1, app1_window, start);
 
-  task_environment().FastForwardBy(kTenMinutes);
+  task_environment()->FastForwardBy(kTenMinutes);
 
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kApp1));
   EXPECT_EQ(kTenMinutes, registry().GetActiveTime(kApp1));
@@ -404,7 +401,7 @@ TEST_F(AppActivityRegistryTest, ResetTimeReached) {
   EXPECT_EQ(kTenMinutes, registry().GetActiveTime(kApp2));
 
   // Now let's make sure
-  task_environment().FastForwardBy(kTenMinutes);
+  task_environment()->FastForwardBy(kTenMinutes);
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kApp2));
   EXPECT_EQ(*limit2.daily_limit(), registry().GetActiveTime(kApp2));
 }
@@ -425,7 +422,7 @@ TEST_F(AppActivityRegistryTest, SharedTimeLimitForChromeAndWebApps) {
 
   // Make chrome active for 30 minutes.
   registry().OnChromeAppActivityChanged(ChromeAppActivityState::kActive, start);
-  task_environment().FastForwardBy(kHalfHour);
+  task_environment()->FastForwardBy(kHalfHour);
   registry().OnChromeAppActivityChanged(ChromeAppActivityState::kInactive,
                                         start + kHalfHour);
 
@@ -451,7 +448,7 @@ TEST_F(AppActivityRegistryTest, SharedTimeLimitForChromeAndWebApps) {
                   chromeos::app_time::AppNotification::kTimeLimitReached))
       .Times(1);
 
-  task_environment().FastForwardBy(kHalfHour);
+  task_environment()->FastForwardBy(kHalfHour);
 
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kApp2));
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kChromeAppId));
@@ -470,7 +467,7 @@ TEST_F(AppActivityRegistryTest, LimitChangedForActiveApp) {
   EXPECT_EQ(base::nullopt, registry().GetTimeLimit(kApp1));
   EXPECT_EQ(base::nullopt, registry_test().GetTimeLeft(kApp1));
 
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(5));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(5));
 
   // Limit set for active app.
   const AppLimit limit1(AppRestriction::kTimeLimit,
@@ -483,7 +480,7 @@ TEST_F(AppActivityRegistryTest, LimitChangedForActiveApp) {
   EXPECT_EQ(base::TimeDelta::FromMinutes(6),
             registry_test().GetTimeLeft(kApp1));
 
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(5));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(5));
 
   EXPECT_TRUE(registry().IsAppActive(kApp1));
   EXPECT_EQ(base::TimeDelta::FromMinutes(10), registry().GetActiveTime(kApp1));
@@ -524,7 +521,7 @@ TEST_F(AppActivityRegistryTest, LimitChangesForInactiveApp) {
   // Use available limit - app should become paused.
   auto* app1_window = CreateWindowForApp(kApp1);
   registry().OnAppActive(kApp1, app1_window, base::Time::Now());
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(5));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(5));
 
   EXPECT_FALSE(registry().IsAppActive(kApp1));
   EXPECT_TRUE(registry().IsAppTimeLimitReached(kApp1));
@@ -633,7 +630,7 @@ TEST_F(AppActivityRegistryTest, RestoredApplicationInformation) {
 
   base::Time app1_start_time_1 = base::Time::Now();
   registry().OnAppActive(kApp1, app1_window, app1_start_time_1);
-  task_environment().FastForwardBy(active_time / 2);
+  task_environment()->FastForwardBy(active_time / 2);
 
   // Save app activity.
   registry_test().SaveAppActivity();
@@ -642,11 +639,11 @@ TEST_F(AppActivityRegistryTest, RestoredApplicationInformation) {
   registry().OnAppInactive(kApp1, app1_window, app1_inactive_time_1);
 
   // App1 is inactive for 5 minutes.
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(5));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(5));
 
   base::Time app1_start_time_2 = base::Time::Now();
   registry().OnAppActive(kApp1, app1_window, app1_start_time_2);
-  task_environment().FastForwardBy(active_time / 2);
+  task_environment()->FastForwardBy(active_time / 2);
 
   // Time limit is reached. App becomes inactive.
   EXPECT_FALSE(registry().IsAppActive(kApp1));
@@ -701,7 +698,7 @@ TEST_F(AppActivityRegistryTest, RemoveUninstalledApplications) {
 
   // App1 has been uninstalled.
   registry().OnAppUninstalled(kApp1);
-  task_environment().FastForwardBy(base::TimeDelta::FromMinutes(10));
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(10));
 
   // Removes kApp1 and cleans up ActiveTimes list in user pref.
   registry().OnSuccessfullyReported(base::Time::Now());
@@ -749,7 +746,7 @@ TEST_F(AppActivityRegistryTest, RemoveOldEntries) {
       prefs::kPerAppTimeLimitsLastSuccessfulReportTime,
       start_time.ToDeltaSinceWindowsEpoch().InMicroseconds());
 
-  task_environment().FastForwardBy(base::TimeDelta::FromDays(30));
+  task_environment()->FastForwardBy(base::TimeDelta::FromDays(30));
 
   // Now let's recreate AppActivityRegistry. Its state should be restored.
   ReInitializeRegistry();

chrome/browser/ui/views/media_router/cast_dialog_no_sinks_view_unittest.cc

@@ -44,7 +44,7 @@ TEST_F(CastDialogNoSinksViewTest, SwitchViews) {
   EXPECT_TRUE(looking_for_sinks_view()->GetVisible());
   EXPECT_FALSE(help_icon_view());
 
-  task_environment_.FastForwardBy(base::TimeDelta::FromSeconds(3));
+  task_environment()->FastForwardBy(base::TimeDelta::FromSeconds(3));
   // After three seconds, only the help icon view should be shown.
   EXPECT_FALSE(looking_for_sinks_view());
   EXPECT_TRUE(help_icon_view()->GetVisible());

chrome/browser/ui/views/tabs/tab_strip_unittest.cc

@@ -1035,13 +1035,13 @@ TEST_P(TabStripTest, AnimationOnTabAdd) {
   const int initial_width = tab_strip_->tab_at(1)->width();
   EXPECT_LT(initial_width, tab_strip_->tab_at(0)->width());
 
-  task_environment_.FastForwardBy(TabAnimation::kAnimationDuration / 2);
+  task_environment()->FastForwardBy(TabAnimation::kAnimationDuration / 2);
 
   EXPECT_GT(tab_strip_->tab_at(1)->width(), initial_width);
   EXPECT_LT(tab_strip_->tab_at(1)->width(), tab_strip_->tab_at(0)->width());
 
   // Fast-forward by more than enough to ensure the animation finishes.
-  task_environment_.FastForwardBy(TabAnimation::kAnimationDuration);
+  task_environment()->FastForwardBy(TabAnimation::kAnimationDuration);
 
   EXPECT_EQ(tab_strip_->tab_at(0)->width(), tab_strip_->tab_at(1)->width());
 }

chrome/test/views/chrome_views_test_base.cc

@@ -5,6 +5,13 @@
 #include "chrome/test/views/chrome_views_test_base.h"
 
 #include "chrome/test/views/chrome_test_views_delegate.h"
+#include "content/public/test/browser_task_environment.h"
+
+ChromeViewsTestBase::ChromeViewsTestBase()
+    : views::ViewsTestBase(std::unique_ptr<base::test::TaskEnvironment>(
+          std::make_unique<content::BrowserTaskEnvironment>(
+              content::BrowserTaskEnvironment::MainThreadType::UI,
+              content::BrowserTaskEnvironment::TimeSource::MOCK_TIME))) {}
 
 ChromeViewsTestBase::~ChromeViewsTestBase() = default;
 

chrome/test/views/chrome_views_test_base.h

@@ -5,46 +5,19 @@
 #ifndef CHROME_TEST_VIEWS_CHROME_VIEWS_TEST_BASE_H_
 #define CHROME_TEST_VIEWS_CHROME_VIEWS_TEST_BASE_H_
 
-#include <memory>
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/traits_bag.h"
-#include "content/public/test/browser_task_environment.h"
 #include "ui/views/test/views_test_base.h"
 
 // A base class for Chrome views unit tests. Changes the dependencies when they
 // need to be different than non-Chrome views.
 class ChromeViewsTestBase : public views::ViewsTestBase {
  public:
-  // Constructs a ChromeViewsTestBase with |traits| being forwarded to its
-  // BrowserTaskEnvironment. MainThreadType always defaults to UI and must not
-  // be specified. TimeSource defaults to MOCK_TIME but can be specified to
-  // override.
-  template <typename... TaskEnvironmentTraits>
-  NOINLINE explicit ChromeViewsTestBase(TaskEnvironmentTraits... traits)
-      : views::ViewsTestBase(
-            views::ViewsTestBase::SubclassManagesTaskEnvironment()),
-        task_environment_(
-            content::BrowserTaskEnvironment::MainThreadType::UI,
-            base::trait_helpers::GetEnum<
-                content::BrowserTaskEnvironment::TimeSource,
-                content::BrowserTaskEnvironment::TimeSource::MOCK_TIME>(
-                traits...),
-            base::trait_helpers::
-                Exclude<content::BrowserTaskEnvironment::TimeSource>::Filter(
-                    traits)...) {}
+  ChromeViewsTestBase();
+  ChromeViewsTestBase(const ChromeViewsTestBase&) = delete;
+  ChromeViewsTestBase& operator=(const ChromeViewsTestBase&) = delete;
   ~ChromeViewsTestBase() override;
 
   // views::ViewsTestBase:
   void SetUp() override;
-
- protected:
-  // Use this protected member directly to drive tasks posted within a
-  // ChromeViewsTestBase-based test.
-  content::BrowserTaskEnvironment task_environment_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeViewsTestBase);
 };
 
 #endif  // CHROME_TEST_VIEWS_CHROME_VIEWS_TEST_BASE_H_

components/media_message_center/media_controls_progress_view_unittest.cc

@@ -120,8 +120,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgress) {
             base::ASCIIToUTF16("05:00"));
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromSeconds(30));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromSeconds(30));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(progress_view_->duration_for_testing(),
             base::ASCIIToUTF16("10:00"));
@@ -143,8 +143,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressFastPlayback) {
             base::ASCIIToUTF16("05:00"));
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromSeconds(15));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromSeconds(15));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(progress_view_->duration_for_testing(),
             base::ASCIIToUTF16("10:00"));
@@ -166,8 +166,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressSlowPlayback) {
             base::ASCIIToUTF16("05:00"));
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromSeconds(60));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromSeconds(60));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(progress_view_->duration_for_testing(),
             base::ASCIIToUTF16("10:00"));
@@ -189,8 +189,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressNegativePlayback) {
             base::ASCIIToUTF16("05:00"));
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromSeconds(30));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromSeconds(30));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(progress_view_->duration_for_testing(),
             base::ASCIIToUTF16("10:00"));
@@ -213,8 +213,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressPastDuration) {
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
   // Move forward in time past the duration.
-  task_environment_->FastForwardBy(base::TimeDelta::FromMinutes(6));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(6));
+  task_environment()->RunUntilIdle();
 
   // Verify the progress does not go past the duration.
   EXPECT_EQ(progress_view_->duration_for_testing(),
@@ -238,8 +238,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressBeforeStart) {
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
   // Move forward in time before the start using negative playback rate.
-  task_environment_->FastForwardBy(base::TimeDelta::FromMinutes(6));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(6));
+  task_environment()->RunUntilIdle();
 
   // Verify the progress does not go below 0.
   EXPECT_EQ(progress_view_->duration_for_testing(),
@@ -262,8 +262,8 @@ TEST_F(MAYBE_MediaControlsProgressViewTest, UpdateProgressPaused) {
             base::ASCIIToUTF16("05:00"));
   EXPECT_EQ(progress_view_->progress_bar_for_testing()->GetValue(), .5);
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromMinutes(6));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(6));
+  task_environment()->RunUntilIdle();
 
   // Verify the progress does not change while media is paused.
   EXPECT_EQ(progress_view_->duration_for_testing(),

components/media_message_center/media_notification_view_impl_unittest.cc

@@ -306,8 +306,7 @@ class MediaNotificationViewImplTest : public views::ViewsTestBase {
   }
 
   void AdvanceClockMilliseconds(int milliseconds) {
-    ASSERT_TRUE(task_environment_.has_value());
-    task_environment_->FastForwardBy(
+    task_environment()->FastForwardBy(
         base::TimeDelta::FromMilliseconds(milliseconds));
   }
 

ui/message_center/views/notification_header_view_unittest.cc

@@ -66,22 +66,22 @@ TEST_F(NotificationHeaderViewTest, UpdatesTimestampOverTime) {
                 IDS_MESSAGE_NOTIFICATION_DURATION_HOURS_SHORTEST_FUTURE, 3),
             timestamp_view->GetText());
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromHours(3));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromHours(3));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(l10n_util::GetPluralStringFUTF16(
                 IDS_MESSAGE_NOTIFICATION_DURATION_MINUTES_SHORTEST_FUTURE, 30),
             timestamp_view->GetText());
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromMinutes(30));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromMinutes(30));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(
       l10n_util::GetStringUTF16(IDS_MESSAGE_NOTIFICATION_NOW_STRING_SHORTEST),
       timestamp_view->GetText());
 
-  task_environment_->FastForwardBy(base::TimeDelta::FromDays(2));
-  task_environment_->RunUntilIdle();
+  task_environment()->FastForwardBy(base::TimeDelta::FromDays(2));
+  task_environment()->RunUntilIdle();
 
   EXPECT_EQ(l10n_util::GetPluralStringFUTF16(
                 IDS_MESSAGE_NOTIFICATION_DURATION_DAYS_SHORTEST, 2),

ui/views/controls/webview/web_dialog_view_unittest.cc

@@ -50,11 +50,9 @@ class TestWebDialogViewWebDialogDelegate
 // Provides functionality to test a WebDialogView.
 class WebDialogViewUnitTest : public views::test::WidgetTest {
  public:
-  template <typename... TaskEnvironmentTraits>
-  NOINLINE explicit WebDialogViewUnitTest(TaskEnvironmentTraits&&... traits)
-      : views::test::WidgetTest(
-            views::test::WidgetTest::SubclassManagesTaskEnvironment()),
-        task_environment_(std::forward<TaskEnvironmentTraits>(traits)...) {}
+  WebDialogViewUnitTest()
+      : views::test::WidgetTest(std::unique_ptr<base::test::TaskEnvironment>(
+            std::make_unique<content::BrowserTaskEnvironment>())) {}
   ~WebDialogViewUnitTest() override = default;
 
   // testing::Test
@@ -127,9 +125,6 @@ class WebDialogViewUnitTest : public views::test::WidgetTest {
       widget_->OnKeyEvent(&event_copy);
   }
 
-  // TaskEnvironment must be created first
-  content::BrowserTaskEnvironment task_environment_;
-
  private:
   content::TestContentBrowserClient test_browser_client_;
   std::unique_ptr<content::TestBrowserContext> browser_context_;

ui/views/controls/webview/webview_unittest.cc

@@ -127,8 +127,9 @@ class WebViewTestWebContentsDelegate : public content::WebContentsDelegate {
 class WebViewUnitTest : public views::test::WidgetTest {
  public:
   WebViewUnitTest()
-      : views::test::WidgetTest(
-            views::ViewsTestBase::SubclassManagesTaskEnvironment()) {}
+      : views::test::WidgetTest(std::unique_ptr<base::test::TaskEnvironment>(
+            std::make_unique<content::BrowserTaskEnvironment>())) {}
+
   ~WebViewUnitTest() override = default;
 
   std::unique_ptr<content::WebContents> CreateWebContentsForWebView(
@@ -193,8 +194,6 @@ class WebViewUnitTest : public views::test::WidgetTest {
     web_view->fullscreen_native_view_for_testing_ = native_view;
   }
 
-  content::BrowserTaskEnvironment task_environment_;
-
  private:
   std::unique_ptr<content::RenderViewHostTestEnabler> rvh_enabler_;
   std::unique_ptr<content::TestBrowserContext> browser_context_;

ui/views/test/views_test_base.cc

@@ -64,7 +64,8 @@ bool InitializeVisuals() {
 }  // namespace
 
 ViewsTestBase::ViewsTestBase(
-    ViewsTestBase::SubclassManagesTaskEnvironment tag) {}
+    std::unique_ptr<base::test::TaskEnvironment> task_environment)
+    : task_environment_(std::move(task_environment)) {}
 
 ViewsTestBase::~ViewsTestBase() {
   CHECK(setup_called_)

ui/views/test/views_test_base.h

@@ -47,16 +47,13 @@ class ViewsTestBase : public PlatformTest {
   // specified.
   template <typename... TaskEnvironmentTraits>
   NOINLINE explicit ViewsTestBase(TaskEnvironmentTraits&&... traits)
-      : task_environment_(base::in_place,
+      : ViewsTestBase(std::make_unique<base::test::TaskEnvironment>(
             base::test::TaskEnvironment::MainThreadType::UI,
-                          std::forward<TaskEnvironmentTraits>(traits)...) {
-  }
+            std::forward<TaskEnvironmentTraits>(traits)...)) {}
 
-  // Alternatively a subclass may pass this tag to ask this ViewsTestBase not to
-  // instantiate a TaskEnvironment. The subclass is then responsible to
-  // instantiate one before ViewsTestBase::SetUp().
-  struct SubclassManagesTaskEnvironment {};
-  explicit ViewsTestBase(SubclassManagesTaskEnvironment tag);
+  // Alternatively a subclass may pass a TaskEnvironment directly.
+  explicit ViewsTestBase(
+      std::unique_ptr<base::test::TaskEnvironment> task_environment);
 
   ~ViewsTestBase() override;
 
@@ -85,6 +82,9 @@ class ViewsTestBase : public PlatformTest {
   void SimulateNativeDestroy(Widget* widget);
 
  protected:
+  base::test::TaskEnvironment* task_environment() {
+    return task_environment_.get();
+  }
   TestViewsDelegate* test_views_delegate() const {
     return test_helper_->test_views_delegate();
   }
@@ -121,16 +121,13 @@ class ViewsTestBase : public PlatformTest {
       const Widget::InitParams& init_params,
       internal::NativeWidgetDelegate* delegate);
 
- protected:
   Widget::InitParams CreateParamsForTestWidget(
       Widget::InitParams::Type type =
           Widget::InitParams::TYPE_WINDOW_FRAMELESS);
 
-  // Initialized first, destroyed last. Use this protected member directly from
-  // the test body to drive tasks posted within a ViewsTestBase-based test.
-  base::Optional<base::test::TaskEnvironment> task_environment_;
-
  private:
+  std::unique_ptr<base::test::TaskEnvironment> task_environment_;
+
   // Controls what type of widget will be created by default for a test (i.e.
   // when creating a Widget and leaving InitParams::native_widget unspecified).
   // kDefault will allow the system default to be used (typically

ui/views/test/widget_test.cc

@@ -16,6 +16,12 @@ void WidgetTest::WidgetCloser::operator()(Widget* widget) const {
   widget->CloseNow();
 }
 
+WidgetTest::WidgetTest() = default;
+
+WidgetTest::WidgetTest(
+    std::unique_ptr<base::test::TaskEnvironment> task_environment)
+    : ViewsTestBase(std::move(task_environment)) {}
+
 WidgetTest::~WidgetTest() = default;
 
 Widget* WidgetTest::CreateTopLevelPlatformWidget() {

ui/views/test/widget_test.h

@@ -46,14 +46,9 @@ class WidgetTest : public ViewsTestBase {
 
   using WidgetAutoclosePtr = std::unique_ptr<Widget, WidgetCloser>;
 
-  // Constructs an AshTestBase with |traits| being forwarded to its
-  // TaskEnvironment. |ViewsTestBase::SubclassManagesTaskEnvironment()|
-  // can also be passed as a sole trait to indicate that this WidgetTest's
-  // subclass will manage the task environment.
-  template <typename... TaskEnvironmentTraits>
-  NOINLINE explicit WidgetTest(TaskEnvironmentTraits&&... traits)
-      : ViewsTestBase(std::forward<TaskEnvironmentTraits>(traits)...) {}
-
+  WidgetTest();
+  explicit WidgetTest(
+      std::unique_ptr<base::test::TaskEnvironment> task_environment);
   ~WidgetTest() override;
 
   // Create Widgets with |native_widget| in InitParams set to an instance of