Fix flakiness in AppMenuTest#testDragHelper_ClickItem

This test was flakily failing due to improper calculation of motion
event x/y coordinates. An animatioin runs when the app menu is opened
and ending it doesn't immediately result in the views reaching their
resting position.

This CL adds a wait for AppMenuDragHelper to be ready for menu item
actions and retrieves the View rect on the UI thread. 0 flakes in 120
runs locally.

BUG=1062236

Change-Id: Ie7264fb23ceaf9e0b6653c7ca78c1b5d2bf555b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2121451Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753694}

chrome/browser/ui/android/appmenu/internal/java/src/org/chromium/chrome/browser/ui/appmenu/AppMenuDragHelper.java

@@ -238,18 +238,9 @@ class AppMenuDragHelper {
      * @return true whether or not a menu item is performed (executed).
      */
     private boolean menuItemAction(int screenX, int screenY, @ItemAction int action) {
-        ListView listView = mAppMenu.getListView();
+        if (!isReadyForMenuItemAction()) return false;
 
-        // Starting M, we have a popup menu animation that slides down. If we process dragging
-        // events while it's sliding, it will touch many views that are passing by user's finger,
-        // which is not desirable. So we only process when the first item is below the menu button.
-        // Unfortunately, there is no available listener for sliding animation finished. Thus the
-        // following nasty heuristics.
-        final View firstRow = listView.getChildAt(0);
-        if (listView.getFirstVisiblePosition() == 0 && firstRow != null && firstRow.getTop() == 0
-                && getScreenVisibleRect(firstRow).bottom <= mMenuButtonScreenCenterY) {
-            return false;
-        }
+        ListView listView = mAppMenu.getListView();
 
         ArrayList<View> itemViews = new ArrayList<View>();
         for (int i = 0; i < listView.getChildCount(); ++i) {
@@ -303,4 +294,22 @@ class AppMenuDragHelper {
         mScreenVisibleRect.offset(mScreenVisiblePoint[0], mScreenVisiblePoint[1]);
         return mScreenVisibleRect;
     }
+
+    @VisibleForTesting
+    boolean isReadyForMenuItemAction() {
+        ListView listView = mAppMenu.getListView();
+
+        // Starting M, we have a popup menu animation that slides down. If we process dragging
+        // events while it's sliding, it will touch many views that are passing by user's finger,
+        // which is not desirable. So we only process when the first item is below the menu button.
+        // Unfortunately, there is no available listener for sliding animation finished. Thus the
+        // following nasty heuristics.
+        final View firstRow = listView.getChildAt(0);
+        if (listView.getFirstVisiblePosition() == 0 && firstRow != null && firstRow.getTop() == 0
+                && getScreenVisibleRect(firstRow).bottom <= mMenuButtonScreenCenterY) {
+            return false;
+        }
+
+        return true;
+    }
 }

chrome/browser/ui/android/appmenu/internal/java/src/org/chromium/chrome/browser/ui/appmenu/AppMenuTest.java

@@ -629,13 +629,13 @@ public class AppMenuTest extends DummyUiActivityTestCase {
                 buttonHelper, mTestMenuButtonDelegate.getMenuButtonView(), downMotionEvent);
 
         waitForMenuToShow(0);
-        Assert.assertTrue("Menu should be showing", mAppMenuHandler.isAppMenuShowing());
+        CriteriaHelper.pollUiThread(
+                () -> mAppMenuHandler.getAppMenuDragHelper().isReadyForMenuItemAction());
+
+        Rect firstItemScreenRect = getVisibleScreenRectAtPosition(0);
+        int eventX = firstItemScreenRect.left + (firstItemScreenRect.width() / 2);
+        int eventY = firstItemScreenRect.top + (firstItemScreenRect.height() / 2);
 
-        View firstItem = mAppMenuHandler.getAppMenu().getListView().getChildAt(0);
-        Rect firstItemScreenRect =
-                mAppMenuHandler.getAppMenuDragHelper().getScreenVisibleRect(firstItem);
-        int eventX = firstItemScreenRect.left + (firstItemScreenRect.right / 2);
-        int eventY = firstItemScreenRect.top + (firstItemScreenRect.bottom / 2);
         MotionEvent dragMotionEvent =
                 MotionEvent.obtain(0, 100, MotionEvent.ACTION_MOVE, eventX, eventY, 0);
         sendMotionEventToButtonHelper(
@@ -645,8 +645,9 @@ public class AppMenuTest extends DummyUiActivityTestCase {
                 MotionEvent.obtain(0, 150, MotionEvent.ACTION_UP, eventX, eventY, 0);
         sendMotionEventToButtonHelper(
                 buttonHelper, mTestMenuButtonDelegate.getMenuButtonView(), upMotionEvent);
-
-        mDelegate.itemSelectedCallbackHelper.waitForCallback(0);
+        mDelegate.itemSelectedCallbackHelper.waitForCallback(
+                "itemRect: " + firstItemScreenRect + " eventX: " + eventX + " eventY: " + eventY,
+                0);
         Assert.assertEquals("Incorrect id for last selected item.", R.id.menu_item_one,
                 mDelegate.lastSelectedItemId);
     }
@@ -739,6 +740,12 @@ public class AppMenuTest extends DummyUiActivityTestCase {
         return viewRect;
     }
 
+    private Rect getVisibleScreenRectAtPosition(int position) throws ExecutionException {
+        View view = getViewAtPosition(position);
+        return TestThreadUtils.runOnUiThreadBlocking(
+                () -> mAppMenuHandler.getAppMenuDragHelper().getScreenVisibleRect(view));
+    }
+
     private void sendMotionEventToButtonHelper(AppMenuButtonHelperImpl helper, View view,
             MotionEvent event) throws ExecutionException {
         TestThreadUtils.runOnUiThreadBlocking(() -> helper.onTouch(view, event));