android_webview/javatests/src/org/chromium/android_webview/test/AwContentsGarbageCollectionTest.java - chromium/src - Git at Google

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.android_webview.test;

 import static org.chromium.android_webview.test.AwActivityTestRule.CHECK_INTERVAL;

 import android.content.Context;
 import android.content.ContextWrapper;
 import android.os.Build;
 import android.os.ResultReceiver;
 import android.support.test.InstrumentationRegistry;
 import android.util.Pair;
 import android.view.Window;
 import android.view.WindowManager;
 import android.webkit.JavascriptInterface;

 import androidx.test.filters.LargeTest;
 import androidx.test.filters.SmallTest;

 import org.hamcrest.Matchers;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;

 import org.chromium.android_webview.AwContents;
 import org.chromium.android_webview.gfx.AwGLFunctor;
 import org.chromium.android_webview.test.AwActivityTestRule.TestDependencyFactory;
 import org.chromium.base.test.util.Criteria;
 import org.chromium.base.test.util.CriteriaHelper;
 import org.chromium.base.test.util.CriteriaNotSatisfiedException;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.MinAndroidSdkLevel;
 import org.chromium.content_public.browser.ImeAdapter;
 import org.chromium.content_public.browser.WebContentsAccessibility;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
 import org.chromium.content_public.common.ContentUrlConstants;

 import java.lang.ref.Reference;
 import java.util.concurrent.Callable;

 /**
  * AwContents garbage collection tests. Most apps relies on WebView being
  * garbage collected to release memory. These tests ensure that nothing
  * accidentally prevents AwContents from garbage collected, leading to leaks.
  * See crbug.com/544098 for why @DisableHardwareAccelerationForTest is needed.
  * These tests are flaky on non-cq L bot (crbug.com/1085101) because the trick
  * to remove InputMethodManager reference does not work on L. This is ok as
  * long as these tests are running and passing on some cq bot, so just
  * disabling them on L.
  */
 @MinAndroidSdkLevel(Build.VERSION_CODES.M)
 @RunWith(AwJUnit4ClassRunner.class)
 public class AwContentsGarbageCollectionTest {
     @Rule
     public AwActivityTestRule mActivityTestRule = new AwActivityTestRule() {
         @Override
         public TestDependencyFactory createTestDependencyFactory() {
             if (mOverridenFactory == null) {
                 return new TestDependencyFactory();
             } else {
                 return mOverridenFactory;
             }
         }
     };

     private TestDependencyFactory mOverridenFactory;

     @After
     public void tearDown() {
         mOverridenFactory = null;
     }

     private static class StrongRefTestContext extends ContextWrapper {
         private AwContents mAwContents;
         public void setAwContentsStrongRef(AwContents awContents) {
             mAwContents = awContents;
         }

         public StrongRefTestContext(Context context) {
             super(context);
         }
     }

     private static class GcTestDependencyFactory extends TestDependencyFactory {
         private final StrongRefTestContext mContext;

         public GcTestDependencyFactory(StrongRefTestContext context) {
             mContext = context;
         }

         @Override
         public AwTestContainerView createAwTestContainerView(
                 AwTestRunnerActivity activity, boolean allowHardwareAcceleration) {
             if (activity != mContext.getBaseContext()) Assert.fail();
             return new AwTestContainerView(mContext, allowHardwareAcceleration);
         }
     }

     private static class StrongRefTestAwContentsClient extends TestAwContentsClient {
         private AwContents mAwContentsStrongRef;
         public void setAwContentsStrongRef(AwContents awContents) {
             mAwContentsStrongRef = awContents;
         }
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testCreateAndGcOneTime() throws Throwable {
         runAwContentsGcTest(() -> {
             TestAwContentsClient client = new TestAwContentsClient();
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mActivityTestRule.loadUrlAsync(
                     containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
             containerView = null;
             return null;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testHoldKeyboardResultReceiver() throws Throwable {
         runAwContentsGcTest(() -> {
             TestAwContentsClient client = new TestAwContentsClient();
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mActivityTestRule.loadUrlAsync(
                     containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
             // When we call showSoftInput(), we pass a ResultReceiver object as a parameter.
             // Android framework will hold the object reference until the matching
             // ResultReceiver in InputMethodService (IME app) gets garbage-collected.
             // WebView object wouldn't get gc'ed once OSK shows up because of this.
             // It is difficult to show keyboard and wait until input method window shows up.
             // Instead, we simply emulate Android's behavior by keeping strong references.
             // See crbug.com/595613 for details.
             ResultReceiver resultReceiver = TestThreadUtils.runOnUiThreadBlocking(
                     () -> ImeAdapter.fromWebContents(containerView.getWebContents())
                                        .getNewShowKeyboardReceiver());

             return resultReceiver;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testAccessibility() throws Throwable {
         runAwContentsGcTest(() -> {
             TestAwContentsClient client = new TestAwContentsClient();
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mActivityTestRule.loadUrlAsync(
                     containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
             TestThreadUtils.runOnUiThreadBlocking(() -> {
                 WebContentsAccessibility webContentsA11y =
                         WebContentsAccessibility.fromWebContents(containerView.getWebContents());
                 webContentsA11y.setState(true);
                 // Enable a11y for testing.
                 webContentsA11y.setAccessibilityEnabledForTesting();
                 // Initialize native object.
                 containerView.getAccessibilityNodeProvider();
                 Assert.assertTrue(webContentsA11y.isAccessibilityEnabled());
             });

             return null;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testReferenceFromClient() throws Throwable {
         runAwContentsGcTest(() -> {
             StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             client.setAwContentsStrongRef(containerView.getAwContents());
             mActivityTestRule.loadUrlAsync(
                     containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);

             containerView = null;
             return null;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testReferenceFromContext() throws Throwable {
         runAwContentsGcTest(() -> {
             TestAwContentsClient client = new TestAwContentsClient();
             StrongRefTestContext context =
                     new StrongRefTestContext(mActivityTestRule.getActivity());
             mOverridenFactory = new GcTestDependencyFactory(context);
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mOverridenFactory = null;
             mActivityTestRule.loadUrlAsync(
                     containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);

             containerView = null;
             return null;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @LargeTest
     @Feature({"AndroidWebView"})
     public void testCreateAndGcManyTimes() throws Throwable {
         runAwContentsGcTest(() -> {
             final int concurrentInstances = 4;
             final int repetitions = 16;

             for (int i = 0; i < repetitions; ++i) {
                 for (int j = 0; j < concurrentInstances; ++j) {
                     StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
                     StrongRefTestContext context =
                             new StrongRefTestContext(mActivityTestRule.getActivity());
                     mOverridenFactory = new GcTestDependencyFactory(context);
                     AwTestContainerView view =
                             mActivityTestRule.createAwTestContainerViewOnMainSync(client);
                     mOverridenFactory = null;
                     // Embedding app can hold onto a strong ref to the WebView from either
                     // WebViewClient or WebChromeClient. That should not prevent WebView from
                     // gc-ed. We simulate that behavior by making the equivalent change here,
                     // have AwContentsClient hold a strong ref to the AwContents object.
                     client.setAwContentsStrongRef(view.getAwContents());
                     context.setAwContentsStrongRef(view.getAwContents());
                     mActivityTestRule.loadUrlAsync(
                             view.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
                 }
                 Assert.assertTrue(AwContents.getNativeInstanceCount() >= concurrentInstances);
                 Assert.assertTrue(
                         AwContents.getNativeInstanceCount() <= (i + 1) * concurrentInstances);
                 removeAllViews();
             }
             return null;
         });
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testGcAfterUsingJavascriptObject() throws Throwable {
         runAwContentsGcTest(() -> {
             // Javascript object with a reference to WebView.
             class Test {
                 Test(int value, AwContents awContents) {
                     mValue = value;
                     mAwContents = awContents;
                 }
                 @JavascriptInterface
                 public int getValue() {
                     return mValue;
                 }
                 public AwContents getAwContents() {
                     return mAwContents;
                 }
                 private int mValue;
                 private AwContents mAwContents;
             }
             String html = "<html>Hello World</html>";
             TestAwContentsClient contentsClient = new TestAwContentsClient();
             AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(contentsClient);
             AwActivityTestRule.enableJavaScriptOnUiThread(containerView.getAwContents());
             final AwContents awContents = containerView.getAwContents();
             final Test jsObject = new Test(42, awContents);
             AwActivityTestRule.addJavascriptInterfaceOnUiThread(awContents, jsObject, "test");
             mActivityTestRule.loadDataSync(
                     awContents, contentsClient.getOnPageFinishedHelper(), html, "text/html", false);
             Assert.assertEquals(String.valueOf(42),
                     mActivityTestRule.executeJavaScriptAndWaitForResult(
                             awContents, contentsClient, "test.getValue()"));

             containerView = null;
             return null;
         });
     }

     // This moves the test body that manipulates AwContents and such objects into
     // a stack frame that's guaranteed to be cleared when the gc checks are run.
     // Otherwise the thread may hold local references (ie from stack variables)
     // to objects.
     private void runAwContentsGcTest(Callable<Object> setup) throws Exception {
         gcAndCheckAllAwContentsDestroyed();
         Object heldObject = setup.call();
         try {
             removeAllViews();

             // This clears a reference that InputMethodManager holds onto focused view.
             TestThreadUtils.runOnUiThreadBlocking(() -> {
                 Window window = mActivityTestRule.getActivity().getWindow();
                 window.addFlags(WindowManager.LayoutParams.FLAG_LOCAL_FOCUS_MODE);
                 window.setLocalFocus(false, false);
                 window.clearFlags(WindowManager.LayoutParams.FLAG_LOCAL_FOCUS_MODE);
             });

             gcAndCheckAllAwContentsDestroyed();
         } finally {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
                 Reference.reachabilityFence(heldObject);
             }
         }
     }

     private void removeAllViews() {
         InstrumentationRegistry.getInstrumentation().runOnMainSync(
                 () -> mActivityTestRule.getActivity().removeAllViews());
     }

     private void gcAndCheckAllAwContentsDestroyed() {
         Runtime.getRuntime().gc();

         Runnable criteria = () -> {
             Pair<Integer, Integer> nativeCounts = null;
             try {
                 nativeCounts = TestThreadUtils.runOnUiThreadBlocking(() -> {
                     return Pair.create(AwContents.getNativeInstanceCount(),
                             AwGLFunctor.getNativeInstanceCount());
                 });
             } catch (Exception e) {
                 throw new CriteriaNotSatisfiedException(e);
             }
             Criteria.checkThat("AwContents count", (int) nativeCounts.first, Matchers.is(0));
             Criteria.checkThat("AwGLFunctor count", (int) nativeCounts.second, Matchers.is(0));
         };

         // Depending on a single gc call can make this test flaky. It's possible
         // that the WebView still has transient references during load so it does not get
         // gc-ed in the one gc-call above. Instead call gc again if exit criteria fails to
         // catch this case.
         final long timeoutBetweenGcMs = 1000L;
         for (int i = 0; i < 15; ++i) {
             try {
                 CriteriaHelper.pollInstrumentationThread(
                         criteria, timeoutBetweenGcMs, CHECK_INTERVAL);
                 break;
             } catch (AssertionError e) {
                 Runtime.getRuntime().gc();
             }
         }

         // Ensure it passes w/o Assertions.
         criteria.run();
     }
 }
	// Copyright 2015 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.android_webview.test;

	import static org.chromium.android_webview.test.AwActivityTestRule.CHECK_INTERVAL;

	import android.content.Context;
	import android.content.ContextWrapper;
	import android.os.Build;
	import android.os.ResultReceiver;
	import android.support.test.InstrumentationRegistry;
	import android.util.Pair;
	import android.view.Window;
	import android.view.WindowManager;
	import android.webkit.JavascriptInterface;

	import androidx.test.filters.LargeTest;
	import androidx.test.filters.SmallTest;

	import org.hamcrest.Matchers;
	import org.junit.After;
	import org.junit.Assert;
	import org.junit.Rule;
	import org.junit.Test;
	import org.junit.runner.RunWith;

	import org.chromium.android_webview.AwContents;
	import org.chromium.android_webview.gfx.AwGLFunctor;
	import org.chromium.android_webview.test.AwActivityTestRule.TestDependencyFactory;
	import org.chromium.base.test.util.Criteria;
	import org.chromium.base.test.util.CriteriaHelper;
	import org.chromium.base.test.util.CriteriaNotSatisfiedException;
	import org.chromium.base.test.util.Feature;
	import org.chromium.base.test.util.MinAndroidSdkLevel;
	import org.chromium.content_public.browser.ImeAdapter;
	import org.chromium.content_public.browser.WebContentsAccessibility;
	import org.chromium.content_public.browser.test.util.TestThreadUtils;
	import org.chromium.content_public.common.ContentUrlConstants;

	import java.lang.ref.Reference;
	import java.util.concurrent.Callable;

	/**
	* AwContents garbage collection tests. Most apps relies on WebView being
	* garbage collected to release memory. These tests ensure that nothing
	* accidentally prevents AwContents from garbage collected, leading to leaks.
	* See crbug.com/544098 for why @DisableHardwareAccelerationForTest is needed.
	* These tests are flaky on non-cq L bot (crbug.com/1085101) because the trick
	* to remove InputMethodManager reference does not work on L. This is ok as
	* long as these tests are running and passing on some cq bot, so just
	* disabling them on L.
	*/
	@MinAndroidSdkLevel(Build.VERSION_CODES.M)
	@RunWith(AwJUnit4ClassRunner.class)
	public class AwContentsGarbageCollectionTest {
	@Rule
	public AwActivityTestRule mActivityTestRule = new AwActivityTestRule() {
	@Override
	public TestDependencyFactory createTestDependencyFactory() {
	if (mOverridenFactory == null) {
	return new TestDependencyFactory();
	} else {
	return mOverridenFactory;
	}
	}
	};

	private TestDependencyFactory mOverridenFactory;

	@After
	public void tearDown() {
	mOverridenFactory = null;
	}

	private static class StrongRefTestContext extends ContextWrapper {
	private AwContents mAwContents;
	public void setAwContentsStrongRef(AwContents awContents) {
	mAwContents = awContents;
	}

	public StrongRefTestContext(Context context) {
	super(context);
	}
	}

	private static class GcTestDependencyFactory extends TestDependencyFactory {
	private final StrongRefTestContext mContext;

	public GcTestDependencyFactory(StrongRefTestContext context) {
	mContext = context;
	}

	@Override
	public AwTestContainerView createAwTestContainerView(
	AwTestRunnerActivity activity, boolean allowHardwareAcceleration) {
	if (activity != mContext.getBaseContext()) Assert.fail();
	return new AwTestContainerView(mContext, allowHardwareAcceleration);
	}
	}

	private static class StrongRefTestAwContentsClient extends TestAwContentsClient {
	private AwContents mAwContentsStrongRef;
	public void setAwContentsStrongRef(AwContents awContents) {
	mAwContentsStrongRef = awContents;
	}
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testCreateAndGcOneTime() throws Throwable {
	runAwContentsGcTest(() -> {
	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mActivityTestRule.loadUrlAsync(
	containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	containerView = null;
	return null;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testHoldKeyboardResultReceiver() throws Throwable {
	runAwContentsGcTest(() -> {
	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mActivityTestRule.loadUrlAsync(
	containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	// When we call showSoftInput(), we pass a ResultReceiver object as a parameter.
	// Android framework will hold the object reference until the matching
	// ResultReceiver in InputMethodService (IME app) gets garbage-collected.
	// WebView object wouldn't get gc'ed once OSK shows up because of this.
	// It is difficult to show keyboard and wait until input method window shows up.
	// Instead, we simply emulate Android's behavior by keeping strong references.
	// See crbug.com/595613 for details.
	ResultReceiver resultReceiver = TestThreadUtils.runOnUiThreadBlocking(
	() -> ImeAdapter.fromWebContents(containerView.getWebContents())
	.getNewShowKeyboardReceiver());

	return resultReceiver;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testAccessibility() throws Throwable {
	runAwContentsGcTest(() -> {
	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mActivityTestRule.loadUrlAsync(
	containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	TestThreadUtils.runOnUiThreadBlocking(() -> {
	WebContentsAccessibility webContentsA11y =
	WebContentsAccessibility.fromWebContents(containerView.getWebContents());
	webContentsA11y.setState(true);
	// Enable a11y for testing.
	webContentsA11y.setAccessibilityEnabledForTesting();
	// Initialize native object.
	containerView.getAccessibilityNodeProvider();
	Assert.assertTrue(webContentsA11y.isAccessibilityEnabled());
	});

	return null;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testReferenceFromClient() throws Throwable {
	runAwContentsGcTest(() -> {
	StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	client.setAwContentsStrongRef(containerView.getAwContents());
	mActivityTestRule.loadUrlAsync(
	containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);

	containerView = null;
	return null;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testReferenceFromContext() throws Throwable {
	runAwContentsGcTest(() -> {
	TestAwContentsClient client = new TestAwContentsClient();
	StrongRefTestContext context =
	new StrongRefTestContext(mActivityTestRule.getActivity());
	mOverridenFactory = new GcTestDependencyFactory(context);
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mOverridenFactory = null;
	mActivityTestRule.loadUrlAsync(
	containerView.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);

	containerView = null;
	return null;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@LargeTest
	@Feature({"AndroidWebView"})
	public void testCreateAndGcManyTimes() throws Throwable {
	runAwContentsGcTest(() -> {
	final int concurrentInstances = 4;
	final int repetitions = 16;

	for (int i = 0; i < repetitions; ++i) {
	for (int j = 0; j < concurrentInstances; ++j) {
	StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
	StrongRefTestContext context =
	new StrongRefTestContext(mActivityTestRule.getActivity());
	mOverridenFactory = new GcTestDependencyFactory(context);
	AwTestContainerView view =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mOverridenFactory = null;
	// Embedding app can hold onto a strong ref to the WebView from either
	// WebViewClient or WebChromeClient. That should not prevent WebView from
	// gc-ed. We simulate that behavior by making the equivalent change here,
	// have AwContentsClient hold a strong ref to the AwContents object.
	client.setAwContentsStrongRef(view.getAwContents());
	context.setAwContentsStrongRef(view.getAwContents());
	mActivityTestRule.loadUrlAsync(
	view.getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	}
	Assert.assertTrue(AwContents.getNativeInstanceCount() >= concurrentInstances);
	Assert.assertTrue(
	AwContents.getNativeInstanceCount() <= (i + 1) * concurrentInstances);
	removeAllViews();
	}
	return null;
	});
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testGcAfterUsingJavascriptObject() throws Throwable {
	runAwContentsGcTest(() -> {
	// Javascript object with a reference to WebView.
	class Test {
	Test(int value, AwContents awContents) {
	mValue = value;
	mAwContents = awContents;
	}
	@JavascriptInterface
	public int getValue() {
	return mValue;
	}
	public AwContents getAwContents() {
	return mAwContents;
	}
	private int mValue;
	private AwContents mAwContents;
	}
	String html = "<html>Hello World</html>";
	TestAwContentsClient contentsClient = new TestAwContentsClient();
	AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(contentsClient);
	AwActivityTestRule.enableJavaScriptOnUiThread(containerView.getAwContents());
	final AwContents awContents = containerView.getAwContents();
	final Test jsObject = new Test(42, awContents);
	AwActivityTestRule.addJavascriptInterfaceOnUiThread(awContents, jsObject, "test");
	mActivityTestRule.loadDataSync(
	awContents, contentsClient.getOnPageFinishedHelper(), html, "text/html", false);
	Assert.assertEquals(String.valueOf(42),
	mActivityTestRule.executeJavaScriptAndWaitForResult(
	awContents, contentsClient, "test.getValue()"));

	containerView = null;
	return null;
	});
	}

	// This moves the test body that manipulates AwContents and such objects into
	// a stack frame that's guaranteed to be cleared when the gc checks are run.
	// Otherwise the thread may hold local references (ie from stack variables)
	// to objects.
	private void runAwContentsGcTest(Callable<Object> setup) throws Exception {
	gcAndCheckAllAwContentsDestroyed();
	Object heldObject = setup.call();
	try {
	removeAllViews();

	// This clears a reference that InputMethodManager holds onto focused view.
	TestThreadUtils.runOnUiThreadBlocking(() -> {
	Window window = mActivityTestRule.getActivity().getWindow();
	window.addFlags(WindowManager.LayoutParams.FLAG_LOCAL_FOCUS_MODE);
	window.setLocalFocus(false, false);
	window.clearFlags(WindowManager.LayoutParams.FLAG_LOCAL_FOCUS_MODE);
	});

	gcAndCheckAllAwContentsDestroyed();
	} finally {
	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
	Reference.reachabilityFence(heldObject);
	}
	}
	}

	private void removeAllViews() {
	InstrumentationRegistry.getInstrumentation().runOnMainSync(
	() -> mActivityTestRule.getActivity().removeAllViews());
	}

	private void gcAndCheckAllAwContentsDestroyed() {
	Runtime.getRuntime().gc();

	Runnable criteria = () -> {
	Pair<Integer, Integer> nativeCounts = null;
	try {
	nativeCounts = TestThreadUtils.runOnUiThreadBlocking(() -> {
	return Pair.create(AwContents.getNativeInstanceCount(),
	AwGLFunctor.getNativeInstanceCount());
	});
	} catch (Exception e) {
	throw new CriteriaNotSatisfiedException(e);
	}
	Criteria.checkThat("AwContents count", (int) nativeCounts.first, Matchers.is(0));
	Criteria.checkThat("AwGLFunctor count", (int) nativeCounts.second, Matchers.is(0));
	};

	// Depending on a single gc call can make this test flaky. It's possible
	// that the WebView still has transient references during load so it does not get
	// gc-ed in the one gc-call above. Instead call gc again if exit criteria fails to
	// catch this case.
	final long timeoutBetweenGcMs = 1000L;
	for (int i = 0; i < 15; ++i) {
	try {
	CriteriaHelper.pollInstrumentationThread(
	criteria, timeoutBetweenGcMs, CHECK_INTERVAL);
	break;
	} catch (AssertionError e) {
	Runtime.getRuntime().gc();
	}
	}

	// Ensure it passes w/o Assertions.
	criteria.run();
	}
	}