Add scrim below TaskMenu

When opening a menu, a scrim with 80% alpha should be shown on top of
Recents view.

Align task menu second row with icon: when the menu shows up in the
bottom row in landscape, the menu should be aligned on the second row.

TODO: there is a RTL bug that I'm waiting because it also affects other
parts, not only this menu.

Bug: 193432925
Test: open Overview and tap the app icon
Change-Id: I6846ee937cb5e739e8be64d17045bc3b32e28e46

quickstep/src/com/android/quickstep/views/RecentsView.java

@@ -2612,10 +2612,8 @@ public abstract class RecentsView<ACTIVITY_TYPE extends StatefulActivity<STATE_T
                         clampToProgress(FINAL_FRAME, 0, 0.5f));
             });
         }
-        boolean isTaskInBottomGridRow = showAsGrid() && !mTopRowIdSet.contains(
-                taskView.getTaskViewId()) && taskView.getTaskViewId() != mFocusedTaskViewId;
         anim.setFloat(taskView, VIEW_ALPHA, 0,
-                clampToProgress(isTaskInBottomGridRow ? ACCEL : FINAL_FRAME, 0, 0.5f));
+                clampToProgress(isOnGridBottomRow(taskView) ? ACCEL : FINAL_FRAME, 0, 0.5f));
         FloatProperty<TaskView> secondaryViewTranslate =
                 taskView.getSecondaryDissmissTranslationProperty();
         int secondaryTaskDimension = mOrientationHandler.getSecondaryDimension(taskView);
@@ -4681,6 +4679,15 @@ public abstract class RecentsView<ACTIVITY_TYPE extends StatefulActivity<STATE_T
         return position != -1 ? position : bottomRowIdArray.indexOf(taskView.getTaskViewId());
     }
 
+    /**
+     * @return true if the task in on the top of the grid
+     */
+    public boolean isOnGridBottomRow(TaskView taskView) {
+        return showAsGrid()
+                && !mTopRowIdSet.contains(taskView.getTaskViewId())
+                && taskView.getTaskViewId() != mFocusedTaskViewId;
+    }
+
     public Consumer<MotionEvent> getEventDispatcher(float navbarRotation) {
         float degreesRotated;
         if (navbarRotation == 0) {