Hide clear-all button from accessibility

This solves muliple navigation problems in Overview.

Bug: 79165501
Change-Id: I2ae99fe3ad24194c9516bb2a99344289ef7408e8
Testing: Manual

quickstep/res/layout/overview_clear_all_button.xml

@@ -11,4 +11,5 @@
     android:textColor="?attr/workspaceTextColor"
     android:visibility="invisible"
     android:textSize="14sp"
+    android:importantForAccessibility="no"
 />

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

@@ -22,7 +22,6 @@ import android.content.Context;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.util.AttributeSet;
-import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.Button;
 
 public class ClearAllButton extends Button {
@@ -36,14 +35,6 @@ public class ClearAllButton extends Button {
         mRecentsView = recentsView;
     }
 
-    @Override
-    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
-        super.onInitializeAccessibilityNodeInfo(info);
-        // Should be visible to accessibility even when completely covered by the task.
-        // Otherwise, we won't be able to scroll to it.
-        info.setVisibleToUser(true);
-    }
-
     @Override
     public boolean performAccessibilityAction(int action, Bundle arguments) {
         final boolean res = super.performAccessibilityAction(action, arguments);

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

@@ -1303,8 +1303,6 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
 
     private void onChildViewsChanged() {
         final int childCount = getChildCount();
-        mClearAllButton.setAccessibilityTraversalAfter(
-                childCount == 0 ? NO_ID : getChildAt(childCount - 1).getId());
         mClearAllButton.setVisibility(childCount == 0 ? INVISIBLE : VISIBLE);
     }