Attempt to deflake TabsTest#testToolbarSwipePrevTab*

This patch updated the toolbar swipe tests to not depend on criteria
helpers and operate on about:blank pages rather than the ntp. Most
importantly, this fixes an issue where we assert tab selection before
waiting for the callback.

Bug: 813584
Change-Id: I1e743291add6398bc3eebc06c03c6c69cefc21f9
Reviewed-on: https://chromium-review.googlesource.com/1044538Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556240}

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

@@ -36,11 +36,11 @@ import org.chromium.base.test.util.Restriction;
 import org.chromium.base.test.util.RetryOnFailure;
 import org.chromium.base.test.util.UrlUtils;
 import org.chromium.chrome.R;
-import org.chromium.chrome.browser.compositor.CompositorViewHolder;
 import org.chromium.chrome.browser.compositor.layouts.Layout;
 import org.chromium.chrome.browser.compositor.layouts.LayoutManager;
 import org.chromium.chrome.browser.compositor.layouts.LayoutManagerChrome;
 import org.chromium.chrome.browser.compositor.layouts.LayoutManagerChromePhone;
+import org.chromium.chrome.browser.compositor.layouts.SceneChangeObserver;
 import org.chromium.chrome.browser.compositor.layouts.StaticLayout;
 import org.chromium.chrome.browser.compositor.layouts.components.LayoutTab;
 import org.chromium.chrome.browser.compositor.layouts.eventfilter.EdgeSwipeHandler;
@@ -50,14 +50,13 @@ import org.chromium.chrome.browser.compositor.layouts.phone.stack.Stack;
 import org.chromium.chrome.browser.compositor.layouts.phone.stack.StackTab;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
-import org.chromium.chrome.browser.tabmodel.EmptyTabModelObserver;
 import org.chromium.chrome.browser.tabmodel.EmptyTabModelSelectorObserver;
 import org.chromium.chrome.browser.tabmodel.TabModel;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabLaunchType;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
-import org.chromium.chrome.browser.tabmodel.TabModelObserver;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
+import org.chromium.chrome.browser.tabmodel.TabModelSelectorTabModelObserver;
 import org.chromium.chrome.browser.tabmodel.TabModelUtils;
 import org.chromium.chrome.browser.tabmodel.TabbedModeTabPersistencePolicy;
 import org.chromium.chrome.browser.toolbar.ToolbarPhone;
@@ -78,6 +77,7 @@ import org.chromium.content.common.ContentSwitches;
 import org.chromium.content_public.browser.SelectionPopupController;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.browser.WebContentsObserver;
+import org.chromium.content_public.common.ContentUrlConstants;
 import org.chromium.net.test.EmbeddedTestServer;
 import org.chromium.ui.test.util.UiRestriction;
 
@@ -155,7 +155,7 @@ public class TabsTest {
                 || mActivityTestRule.getName().equals("testIncognitoTabsNotRestoredAfterSwipe")) {
             return;
         }
-        mActivityTestRule.startMainActivityFromLauncher();
+        mActivityTestRule.startMainActivityOnBlankPage();
     }
 
 
@@ -1558,8 +1558,8 @@ public class TabsTest {
     @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
     @RetryOnFailure
     public void testToolbarSwipeNextThenPrevTab() throws InterruptedException, TimeoutException {
-        ChromeTabUtils.newTabFromMenu(
-                InstrumentationRegistry.getInstrumentation(), mActivityTestRule.getActivity());
+        ChromeTabUtils.fullyLoadUrlInNewTab(InstrumentationRegistry.getInstrumentation(),
+                mActivityTestRule.getActivity(), ContentUrlConstants.ABOUT_BLANK_URL, false);
         ChromeTabUtils.switchTabInCurrentTabModel(mActivityTestRule.getActivity(), 0);
         UiUtils.settleDownUI(InstrumentationRegistry.getInstrumentation());
 
@@ -1580,8 +1580,10 @@ public class TabsTest {
     @RetryOnFailure
     public void testToolbarSwipeNextThenPrevTabIncognito()
             throws InterruptedException, TimeoutException {
-        mActivityTestRule.newIncognitoTabFromMenu();
-        mActivityTestRule.newIncognitoTabFromMenu();
+        ChromeTabUtils.fullyLoadUrlInNewTab(InstrumentationRegistry.getInstrumentation(),
+                mActivityTestRule.getActivity(), ContentUrlConstants.ABOUT_BLANK_URL, true);
+        ChromeTabUtils.fullyLoadUrlInNewTab(InstrumentationRegistry.getInstrumentation(),
+                mActivityTestRule.getActivity(), ContentUrlConstants.ABOUT_BLANK_URL, true);
         ChromeTabUtils.switchTabInCurrentTabModel(mActivityTestRule.getActivity(), 0);
         UiUtils.settleDownUI(InstrumentationRegistry.getInstrumentation());
 
@@ -1598,40 +1600,41 @@ public class TabsTest {
     private void runToolbarSideSwipeTestOnCurrentModel(ScrollDirection direction, int finalIndex,
             boolean expectsSelection) throws InterruptedException, TimeoutException {
         final CallbackHelper selectCallback = new CallbackHelper();
-        final int id =
-                mActivityTestRule.getActivity().getCurrentTabModel().getTabAt(finalIndex).getId();
-        final TabModelObserver observer = new EmptyTabModelObserver() {
+        final ChromeTabbedActivity activity = mActivityTestRule.getActivity();
+        final int id = activity.getCurrentTabModel().getTabAt(finalIndex).getId();
+        final TabModelSelectorTabModelObserver observer = new TabModelSelectorTabModelObserver(
+                activity.getTabModelSelector()) {
             @Override
             public void didSelectTab(Tab tab, TabSelectionType type, int lastId) {
                 if (tab.getId() == id) selectCallback.notifyCalled();
             }
         };
 
-        if (expectsSelection) {
-            ThreadUtils.runOnUiThreadBlocking(() -> {
-                TabModelSelector selector = mActivityTestRule.getActivity().getTabModelSelector();
-                for (TabModel tabModel : selector.getModels()) {
-                    tabModel.addObserver(observer);
+        // Listen for changes in the layout to indicate the swipe has completed.
+        final CallbackHelper staticLayoutCallbackHelper = new CallbackHelper();
+        activity.getCompositorViewHolder().getLayoutManager().addSceneChangeObserver(
+                new SceneChangeObserver() {
+                    @Override
+                    public void onTabSelectionHinted(int tabId) {}
+
+                    @Override
+                    public void onSceneChange(Layout layout) {
+                        if (layout instanceof StaticLayout) {
+                            staticLayoutCallbackHelper.notifyCalled();
                         }
-            });
                     }
+                });
 
+        int callCount = staticLayoutCallbackHelper.getCallCount();
         performToolbarSideSwipe(direction);
-        waitForStaticLayout();
-        Assert.assertEquals("Index after toolbar side swipe is incorrect", finalIndex,
-                mActivityTestRule.getActivity().getCurrentTabModel().index());
+        staticLayoutCallbackHelper.waitForCallback(callCount, 1);
 
-        if (expectsSelection) {
-            selectCallback.waitForCallback(0);
-            ThreadUtils.runOnUiThreadBlocking(() -> {
-                TabModelSelector selector = mActivityTestRule.getActivity().getTabModelSelector();
-                for (TabModel tabModel : selector.getModels()) {
-                    tabModel.removeObserver(observer);
-                }
-            });
-        }
-    }
+        if (expectsSelection) selectCallback.waitForCallback(0);
+        ThreadUtils.runOnUiThreadBlocking(() -> observer.destroy());
 
+        Assert.assertEquals("Index after toolbar side swipe is incorrect", finalIndex,
+                activity.getCurrentTabModel().index());
+    }
 
     private void performToolbarSideSwipe(ScrollDirection direction) {
         Assert.assertTrue("Unexpected direction for side swipe " + direction,
@@ -1653,21 +1656,6 @@ public class TabsTest {
         TouchCommon.dragEnd(mActivityTestRule.getActivity(), toX, y, downTime);
     }
 
-    private void waitForStaticLayout() throws InterruptedException {
-        CriteriaHelper.pollUiThread(
-                new Criteria("Static Layout never selected after side swipe") {
-                    @Override
-                    public boolean isSatisfied() {
-                        CompositorViewHolder compositorViewHolder =
-                                (CompositorViewHolder) mActivityTestRule.getActivity().findViewById(
-                                        R.id.compositor_view_holder);
-                        LayoutManager layoutManager = compositorViewHolder.getLayoutManager();
-
-                        return layoutManager.getActiveLayout() instanceof StaticLayout;
-                    }
-                });
-    }
-
     /**
      * Test that swipes and tab transitions are not causing URL bar to be focused.
      */