Merge "Fix the flaky test case : testRecentsButtonDisabledOnSecondaryDisplay"

import android.hardware.display.DisplayManager;

import android.hardware.display.VirtualDisplay;

import android.media.ImageReader;

import android.os.SystemClock;

import android.support.test.filters.SmallTest;

import android.testing.AndroidTestingRunner;

import android.testing.TestableLooper.RunWithLooper;

import android.util.Log;

import android.view.Display;

import android.view.DisplayInfo;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.util.function.Predicate;

/** atest NavigationBarButtonTest */

@RunWith(AndroidTestingRunner.class)

@RunWithLooper

@SmallTest

public class NavigationBarButtonTest extends SysuiTestCase {

    private static final String TAG = "NavigationBarButtonTest";

    private ImageReader mReader;

    private NavigationBarView mNavBar;

    private VirtualDisplay mVirtualDisplay;

        assertNotNull("virtual display must not be null", mVirtualDisplay);

        waitForDisplayReady(mVirtualDisplay.getDisplay().getDisplayId());

        return mVirtualDisplay.getDisplay();

    }

    private void waitForDisplayReady(int displayId) {

        waitForDisplayCondition(displayId, state -> state);

    }

    private void waitForDisplayCondition(int displayId, Predicate<Boolean> condition) {

        for (int retry = 1; retry <= 10; retry++) {

            if (condition.test(isDisplayOn(displayId))) {

                return;

            }

            Log.i(TAG, "Waiting for virtual display ready ... retry = " + retry);

            SystemClock.sleep(500);

        }

    }

    private boolean isDisplayOn(int displayId) {

        DisplayManager displayManager = mContext.getSystemService(DisplayManager.class);

        Display display = displayManager.getDisplay(displayId);

        return display != null && display.getState() == Display.STATE_ON;

    }

    @After

    public void tearDown() {

        releaseDisplay();