Revert "Add tests for undo closure in stack tab switcher"

This reverts commit e3d5c44e.

Reason for revert: Flaky failures on multiple bots
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=chrome_public_test_apk&tests=org.chromium.chrome.browser.TabsTest%23testUndo

Original change's description:
> Add tests for undo closure in stack tab switcher
> 
> Bug: 1064445
> Change-Id: I31bf5c42e013868282d1d220d7d871f411331494
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2150060
> Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
> Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
> Reviewed-by: Mei Liang <meiliang@chromium.org>
> Commit-Queue: Yue Zhang <yuezhanggg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#761720}

TBR=yusufo@chromium.org,wychen@chromium.org,meiliang@chromium.org,yuezhanggg@chromium.org

Change-Id: I447c525cdf6da5c69e200f775804fde888e67f9f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1064445
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163386Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#761971}

chrome/android/javatests/src/org/chromium/chrome/browser/TabsTest.java

@@ -6,14 +6,9 @@ package org.chromium.chrome.browser;
 
 import static android.support.test.espresso.Espresso.onView;
 import static android.support.test.espresso.action.ViewActions.click;
-import static android.support.test.espresso.assertion.ViewAssertions.doesNotExist;
-import static android.support.test.espresso.matcher.ViewMatchers.isCompletelyDisplayed;
 import static android.support.test.espresso.matcher.ViewMatchers.withId;
 
-import static org.hamcrest.Matchers.allOf;
-
 import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
-import static org.chromium.chrome.test.util.ViewUtils.onViewWaiting;
 
 import android.content.pm.ActivityInfo;
 import android.graphics.Point;
@@ -999,7 +994,7 @@ public class TabsTest {
         final int[] count = new int[1];
         TestThreadUtils.runOnUiThreadBlocking(() -> {
             Stack stack = getStack(layoutManager, isIncognito);
-            count[0] = stack.getCount();
+            count[0] = stack.getTabs().length;
         });
         return count[0];
     }
@@ -1863,95 +1858,6 @@ public class TabsTest {
         assertFileExists(incognitoTabFile, false);
     }
 
-    @Test
-    @MediumTest
-    @Feature({"Android-TabSwitcher"})
-    public void testUndoNormalTabClosure() {
-        ChromeTabbedActivity cta = mActivityTestRule.getActivity();
-        TabModel normalTabModel = cta.getTabModelSelector().getModel(false);
-        for (int i = 0; i < 3; i++) {
-            ChromeTabUtils.newTabFromMenu(InstrumentationRegistry.getInstrumentation(), cta);
-        }
-        showOverviewAndWaitForAnimation();
-        CriteriaHelper.pollUiThread(Criteria.equals(4, () -> getLayoutTabInStackCount(false)));
-        Assert.assertEquals(4, normalTabModel.getCount());
-        // Close two normal tabs.
-        swipeToCloseNTabs(2, false, false, SWIPE_TO_LEFT_DIRECTION);
-        CriteriaHelper.pollUiThread(Criteria.equals(2, () -> getLayoutTabInStackCount(false)));
-        Assert.assertEquals(2, normalTabModel.getCount());
-        // Click the undo button on snackbar twice to undo two closures.
-        verifyUndoBarShowingAndClickUndo();
-        CriteriaHelper.pollUiThread(Criteria.equals(3, () -> getLayoutTabInStackCount(false)));
-        Assert.assertEquals(3, normalTabModel.getCount());
-        verifyUndoBarShowingAndClickUndo();
-        CriteriaHelper.pollUiThread(Criteria.equals(4, () -> getLayoutTabInStackCount(false)));
-        Assert.assertEquals(4, normalTabModel.getCount());
-    }
-
-    @Test
-    @MediumTest
-    @Feature({"Android-TabSwitcher"})
-    public void testUndoIncognitoTabClosure() {
-        ChromeTabbedActivity cta = mActivityTestRule.getActivity();
-        TabModel incognitoTabModel = cta.getTabModelSelector().getModel(true);
-        for (int i = 0; i < 4; i++) {
-            mActivityTestRule.newIncognitoTabFromMenu();
-        }
-        showOverviewAndWaitForAnimation();
-        CriteriaHelper.pollUiThread(Criteria.equals(4, () -> getLayoutTabInStackCount(true)));
-        Assert.assertEquals(4, incognitoTabModel.getCount());
-        // Close one incognito tab.
-        swipeToCloseNTabs(1, false, true, SWIPE_TO_LEFT_DIRECTION);
-        CriteriaHelper.pollUiThread(Criteria.equals(3, () -> getLayoutTabInStackCount(true)));
-        Assert.assertEquals(3, incognitoTabModel.getCount());
-        // The undo snackbar should never show.
-        onView(withId(R.id.snackbar_button)).check(doesNotExist());
-        Assert.assertFalse(cta.getSnackbarManager().isShowing());
-    }
-
-    @Test
-    @MediumTest
-    @Feature({"Android-TabSwitcher"})
-    // This test fails on API 23 emulators because the snack bar animation is not playing properly.
-    public void testUndoAllTabsClosure() throws InterruptedException {
-        ChromeTabbedActivity cta = mActivityTestRule.getActivity();
-        TabModel normalTabModel = cta.getTabModelSelector().getModel(false);
-        TabModel incognitoTabModel = cta.getTabModelSelector().getModel(true);
-        for (int i = 0; i < 2; i++) {
-            ChromeTabUtils.newTabFromMenu(InstrumentationRegistry.getInstrumentation(), cta);
-        }
-        for (int i = 0; i < 2; i++) {
-            mActivityTestRule.newIncognitoTabFromMenu();
-        }
-        showOverviewAndWaitForAnimation();
-        CriteriaHelper.pollUiThread(Criteria.equals(3, () -> getLayoutTabInStackCount(false)));
-        CriteriaHelper.pollUiThread(Criteria.equals(2, () -> getLayoutTabInStackCount(true)));
-        Assert.assertEquals(3, normalTabModel.getCount());
-        Assert.assertEquals(2, incognitoTabModel.getCount());
-        // Close all tabs through menu option.
-        MenuUtils.invokeCustomMenuActionSync(
-                InstrumentationRegistry.getInstrumentation(), cta, R.id.close_all_tabs_menu_id);
-        CriteriaHelper.pollUiThread(Criteria.equals(0, () -> getLayoutTabInStackCount(false)));
-        CriteriaHelper.pollUiThread(Criteria.equals(0, () -> getLayoutTabInStackCount(true)));
-        Assert.assertEquals(0, normalTabModel.getCount());
-        Assert.assertEquals(0, incognitoTabModel.getCount());
-        // Click the undo button on snackbar and should only undo closure of normal tabs.
-        verifyUndoBarShowingAndClickUndo();
-        CriteriaHelper.pollUiThread(Criteria.equals(3, () -> getLayoutTabInStackCount(false)));
-        CriteriaHelper.pollUiThread(Criteria.equals(0, () -> getLayoutTabInStackCount(true)));
-        Assert.assertEquals(3, normalTabModel.getCount());
-        Assert.assertEquals(0, incognitoTabModel.getCount());
-    }
-
-    /**
-     * Verify that the snack bar is showing and click on the snack bar button. Right now it is only
-     * used for undoing a tab closure.
-     */
-    private void verifyUndoBarShowingAndClickUndo() {
-        onViewWaiting(allOf(withId(R.id.snackbar), isCompletelyDisplayed()));
-        onView(withId(R.id.snackbar_button)).perform(click());
-    }
-
     /**
      * Generate a URL that shows a web page with a solid color. This makes visual debugging easier.
      * @param htmlColor The HTML/CSS color the page should display.