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 static org.chromium.base.test.util.ScalableTimeout.scaleTimeout;

 import android.content.Context;
 import android.content.ContextWrapper;
 import android.os.ResultReceiver;
 import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.LargeTest;
 import android.support.test.filters.SmallTest;
 import android.webkit.JavascriptInterface;

 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.Feature;
 import org.chromium.content_public.browser.ImeAdapter;
 import org.chromium.content_public.browser.WebContentsAccessibility;
 import org.chromium.content_public.browser.test.util.Criteria;
 import org.chromium.content_public.browser.test.util.CriteriaHelper;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
 import org.chromium.content_public.common.ContentUrlConstants;

 /**
  * 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.
  */
 @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;
             }
         }
     };

     // The system retains a strong ref to the last focused view (in InputMethodManager)
     // so allow for 1 'leaked' instance.
     private static final int MAX_IDLE_INSTANCES = 1;

     private TestDependencyFactory mOverridenFactory;

     @After
     public void tearDown() throws Exception {
         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 {
         gcAndCheckAllAwContentsDestroyed();

         TestAwContentsClient client = new TestAwContentsClient();
         AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mActivityTestRule.loadUrlAsync(
                     containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
         }

         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = null;
         }
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testHoldKeyboardResultReceiver() throws Throwable {
         gcAndCheckAllAwContentsDestroyed();

         TestAwContentsClient client = new TestAwContentsClient();
         AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
         ResultReceiver resultReceivers[] = new ResultReceiver[MAX_IDLE_INSTANCES + 1];
         for (int i = 0; i < containerViews.length; i++) {
             final AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             containerViews[i] = containerView;
             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.
             resultReceivers[i] = TestThreadUtils.runOnUiThreadBlocking(
                     () -> ImeAdapter.fromWebContents(containerView.getWebContents())
                                        .getNewShowKeyboardReceiver());
         }

         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = null;
         }
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testAccessibility() throws Throwable {
         gcAndCheckAllAwContentsDestroyed();

         TestAwContentsClient client = new TestAwContentsClient();
         AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
         for (int i = 0; i < containerViews.length; i++) {
             final AwTestContainerView containerView =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             containerViews[i] = containerView;
             mActivityTestRule.loadUrlAsync(
                     containerViews[i].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());
             });
         }

         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = null;
         }
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testReferenceFromClient() throws Throwable {
         gcAndCheckAllAwContentsDestroyed();

         AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
         for (int i = 0; i < containerViews.length; i++) {
             StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
             containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mActivityTestRule.loadUrlAsync(
                     containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
         }

         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = null;
         }
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testReferenceFromContext() throws Throwable {
         gcAndCheckAllAwContentsDestroyed();

         TestAwContentsClient client = new TestAwContentsClient();
         AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
         for (int i = 0; i < containerViews.length; i++) {
             StrongRefTestContext context =
                     new StrongRefTestContext(mActivityTestRule.getActivity());
             mOverridenFactory = new GcTestDependencyFactory(context);
             containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
             mOverridenFactory = null;
             mActivityTestRule.loadUrlAsync(
                     containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
         }

         for (int i = 0; i < containerViews.length; i++) {
             containerViews[i] = null;
         }
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @LargeTest
     @Feature({"AndroidWebView"})
     public void testCreateAndGcManyTimes() throws Throwable {
         gcAndCheckAllAwContentsDestroyed();

         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();
         }

         gcAndCheckAllAwContentsDestroyed();
     }

     @Test
     @DisableHardwareAccelerationForTest
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testGcAfterUsingJavascriptObject() throws Throwable {
         // 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>";
         AwTestContainerView[] containerViews = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];

         TestAwContentsClient contentsClient = new TestAwContentsClient();
         for (int i = 0; i < MAX_IDLE_INSTANCES + 1; ++i) {
             containerViews[i] =
                     mActivityTestRule.createAwTestContainerViewOnMainSync(contentsClient);
             AwActivityTestRule.enableJavaScriptOnUiThread(containerViews[i].getAwContents());
             final AwContents awContents = containerViews[i].getAwContents();
             final Test jsObject = new Test(i, awContents);
             AwActivityTestRule.addJavascriptInterfaceOnUiThread(awContents, jsObject, "test");
             mActivityTestRule.loadDataSync(
                     awContents, contentsClient.getOnPageFinishedHelper(), html, "text/html", false);
             Assert.assertEquals(String.valueOf(i),
                     mActivityTestRule.executeJavaScriptAndWaitForResult(
                             awContents, contentsClient, "test.getValue()"));
         }

         containerViews[0] = null;
         containerViews[1] = null;
         containerViews = null;
         removeAllViews();
         gcAndCheckAllAwContentsDestroyed();
     }

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

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

         Criteria criteria = new Criteria() {
             @Override
             public boolean isSatisfied() {
                 try {
                     return TestThreadUtils.runOnUiThreadBlocking(() -> {
                         int count_aw_contents = AwContents.getNativeInstanceCount();
                         int count_aw_functor = AwGLFunctor.getNativeInstanceCount();
                         return count_aw_contents <= MAX_IDLE_INSTANCES
                                 && count_aw_functor <= MAX_IDLE_INSTANCES;
                     });
                 } catch (Exception e) {
                     return false;
                 }
             }
         };

         // 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 = scaleTimeout(1000);
         for (int i = 0; i < 15; ++i) {
             try {
                 CriteriaHelper.pollInstrumentationThread(
                         criteria, timeoutBetweenGcMs, CHECK_INTERVAL);
                 break;
             } catch (AssertionError e) {
                 Runtime.getRuntime().gc();
             }
         }

         Assert.assertTrue(criteria.isSatisfied());
     }
 }
	// 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 static org.chromium.base.test.util.ScalableTimeout.scaleTimeout;

	import android.content.Context;
	import android.content.ContextWrapper;
	import android.os.ResultReceiver;
	import android.support.test.InstrumentationRegistry;
	import android.support.test.filters.LargeTest;
	import android.support.test.filters.SmallTest;
	import android.webkit.JavascriptInterface;

	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.Feature;
	import org.chromium.content_public.browser.ImeAdapter;
	import org.chromium.content_public.browser.WebContentsAccessibility;
	import org.chromium.content_public.browser.test.util.Criteria;
	import org.chromium.content_public.browser.test.util.CriteriaHelper;
	import org.chromium.content_public.browser.test.util.TestThreadUtils;
	import org.chromium.content_public.common.ContentUrlConstants;

	/**
	* 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.
	*/
	@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;
	}
	}
	};

	// The system retains a strong ref to the last focused view (in InputMethodManager)
	// so allow for 1 'leaked' instance.
	private static final int MAX_IDLE_INSTANCES = 1;

	private TestDependencyFactory mOverridenFactory;

	@After
	public void tearDown() throws Exception {
	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 {
	gcAndCheckAllAwContentsDestroyed();

	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mActivityTestRule.loadUrlAsync(
	containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	}

	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = null;
	}
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testHoldKeyboardResultReceiver() throws Throwable {
	gcAndCheckAllAwContentsDestroyed();

	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
	ResultReceiver resultReceivers[] = new ResultReceiver[MAX_IDLE_INSTANCES + 1];
	for (int i = 0; i < containerViews.length; i++) {
	final AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	containerViews[i] = containerView;
	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.
	resultReceivers[i] = TestThreadUtils.runOnUiThreadBlocking(
	() -> ImeAdapter.fromWebContents(containerView.getWebContents())
	.getNewShowKeyboardReceiver());
	}

	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = null;
	}
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testAccessibility() throws Throwable {
	gcAndCheckAllAwContentsDestroyed();

	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
	for (int i = 0; i < containerViews.length; i++) {
	final AwTestContainerView containerView =
	mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	containerViews[i] = containerView;
	mActivityTestRule.loadUrlAsync(
	containerViews[i].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());
	});
	}

	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = null;
	}
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testReferenceFromClient() throws Throwable {
	gcAndCheckAllAwContentsDestroyed();

	AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
	for (int i = 0; i < containerViews.length; i++) {
	StrongRefTestAwContentsClient client = new StrongRefTestAwContentsClient();
	containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mActivityTestRule.loadUrlAsync(
	containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	}

	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = null;
	}
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testReferenceFromContext() throws Throwable {
	gcAndCheckAllAwContentsDestroyed();

	TestAwContentsClient client = new TestAwContentsClient();
	AwTestContainerView containerViews[] = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];
	for (int i = 0; i < containerViews.length; i++) {
	StrongRefTestContext context =
	new StrongRefTestContext(mActivityTestRule.getActivity());
	mOverridenFactory = new GcTestDependencyFactory(context);
	containerViews[i] = mActivityTestRule.createAwTestContainerViewOnMainSync(client);
	mOverridenFactory = null;
	mActivityTestRule.loadUrlAsync(
	containerViews[i].getAwContents(), ContentUrlConstants.ABOUT_BLANK_DISPLAY_URL);
	}

	for (int i = 0; i < containerViews.length; i++) {
	containerViews[i] = null;
	}
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@LargeTest
	@Feature({"AndroidWebView"})
	public void testCreateAndGcManyTimes() throws Throwable {
	gcAndCheckAllAwContentsDestroyed();

	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();
	}

	gcAndCheckAllAwContentsDestroyed();
	}

	@Test
	@DisableHardwareAccelerationForTest
	@SmallTest
	@Feature({"AndroidWebView"})
	public void testGcAfterUsingJavascriptObject() throws Throwable {
	// 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>";
	AwTestContainerView[] containerViews = new AwTestContainerView[MAX_IDLE_INSTANCES + 1];

	TestAwContentsClient contentsClient = new TestAwContentsClient();
	for (int i = 0; i < MAX_IDLE_INSTANCES + 1; ++i) {
	containerViews[i] =
	mActivityTestRule.createAwTestContainerViewOnMainSync(contentsClient);
	AwActivityTestRule.enableJavaScriptOnUiThread(containerViews[i].getAwContents());
	final AwContents awContents = containerViews[i].getAwContents();
	final Test jsObject = new Test(i, awContents);
	AwActivityTestRule.addJavascriptInterfaceOnUiThread(awContents, jsObject, "test");
	mActivityTestRule.loadDataSync(
	awContents, contentsClient.getOnPageFinishedHelper(), html, "text/html", false);
	Assert.assertEquals(String.valueOf(i),
	mActivityTestRule.executeJavaScriptAndWaitForResult(
	awContents, contentsClient, "test.getValue()"));
	}

	containerViews[0] = null;
	containerViews[1] = null;
	containerViews = null;
	removeAllViews();
	gcAndCheckAllAwContentsDestroyed();
	}

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

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

	Criteria criteria = new Criteria() {
	@Override
	public boolean isSatisfied() {
	try {
	return TestThreadUtils.runOnUiThreadBlocking(() -> {
	int count_aw_contents = AwContents.getNativeInstanceCount();
	int count_aw_functor = AwGLFunctor.getNativeInstanceCount();
	return count_aw_contents <= MAX_IDLE_INSTANCES
	&& count_aw_functor <= MAX_IDLE_INSTANCES;
	});
	} catch (Exception e) {
	return false;
	}
	}
	};

	// 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 = scaleTimeout(1000);
	for (int i = 0; i < 15; ++i) {
	try {
	CriteriaHelper.pollInstrumentationThread(
	criteria, timeoutBetweenGcMs, CHECK_INTERVAL);
	break;
	} catch (AssertionError e) {
	Runtime.getRuntime().gc();
	}
	}

	Assert.assertTrue(criteria.isSatisfied());
	}
	}