[WebLayer] Handle accessibility in infobars

This CL augments WebLayer's infobars implementation by handling
accessibility as Chrome's does: while accessibility is enabled the
infobar container view does not scroll out of view. The implementation
is a port of that of //chrome's InfoBarContainer.java extended to
handle the wrinkle that WebLayerAccessibilityUtil drops its observers
when there are no more Browsers and doesn't re-add them on addition of
a new Browser.

Bug: 1093846
Change-Id: Ic58d17823068d60c9d0d25a80f7ddcf420f9a2fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2254020
Commit-Queue: Colin Blundell <blundell@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781801}

weblayer/browser/android/javatests/src/org/chromium/weblayer/test/InfoBarTest.java

@@ -17,6 +17,7 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CallbackHelper;
 import org.chromium.base.test.util.CommandLineFlags;
+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.weblayer.Browser;
@@ -65,6 +66,26 @@ public class InfoBarTest {
         helper.waitForFirst();
     }
 
+    private void setAccessibilityEnabled(boolean value) {
+        TestThreadUtils.runOnUiThreadBlocking(() -> {
+            try {
+                getTestWebLayer().setAccessibilityEnabled(value);
+            } catch (RemoteException e) {
+                throw new RuntimeException(e);
+            }
+        });
+    }
+
+    private boolean canInfoBarContainerScroll() throws Exception {
+        return TestThreadUtils.runOnUiThreadBlocking(() -> {
+            try {
+                return getTestWebLayer().canInfoBarContainerScroll(getActiveTab());
+            } catch (RemoteException e) {
+                throw new RuntimeException(e);
+            }
+        });
+    }
+
     @Before
     public void setUp() throws Throwable {
         final String url = mActivityTestRule.getTestDataURL("tall_page.html");
@@ -155,4 +176,22 @@ public class InfoBarTest {
         mActivityTestRule.navigateAndWait("about:blank");
         Assert.assertEquals(infoBarContainerView.getVisibility(), View.VISIBLE);
     }
+
+    // Tests that infobar container is blocked from scrolling when accessibility is enabled.
+    @Test
+    @SmallTest
+    public void testAccessibility() throws Exception {
+        InstrumentationActivity activity = mActivityTestRule.getActivity();
+
+        // Turn on accessibility, which should disable the infobar container from scrolling. This
+        // polls as setAccessibilityEnabled() is async.
+        setAccessibilityEnabled(true);
+        CriteriaHelper.pollInstrumentationThread(
+                Criteria.equals(false, () -> canInfoBarContainerScroll()));
+
+        // Turn accessibility off and verify that the infobar container can scroll.
+        setAccessibilityEnabled(false);
+        CriteriaHelper.pollInstrumentationThread(
+                Criteria.equals(true, () -> canInfoBarContainerScroll()));
+    }
 }

weblayer/browser/java/org/chromium/weblayer_private/InfoBarContainer.java

@@ -20,6 +20,7 @@ import org.chromium.content_public.browser.NavigationHandle;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.browser.WebContentsObserver;
 import org.chromium.ui.KeyboardVisibilityDelegate.KeyboardVisibilityListener;
+import org.chromium.ui.util.AccessibilityUtil;
 
 import java.util.ArrayList;
 
@@ -33,7 +34,19 @@ import java.util.ArrayList;
 public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Container {
     private static final String TAG = "InfoBarContainer";
 
-    // TODO(crbug.com/1025620): Port over //chrome's listening to AccessibilityUtil if/as needed.
+    // Number of instances that have not been destroyed.
+    private static int sInstanceCount;
+
+    // InfoBarContainer's handling of accessibility is a global toggle, and thus a static observer
+    // suffices. However, observing accessibility events has the wrinkle that all accessibility
+    // observers are removed when there are no more Browsers and are not re-added if a new Browser
+    // is subsequently created. To handle this wrinkle, |sAccessibilityObserver| is added as an
+    // observer whenever the number of non-destroyed InfoBarContainers becomes non-zero and removed
+    // whenever that number flips to zero.
+    private static final AccessibilityUtil.Observer sAccessibilityObserver;
+    static {
+        sAccessibilityObserver = (enabled) -> setIsAllowedToAutoHide(!enabled);
+    }
 
     /**
      * A listener for the InfoBar animations.
@@ -166,6 +179,10 @@ public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Con
     private @Nullable InfoBarContainerView mInfoBarContainerView;
 
     InfoBarContainer(TabImpl tab) {
+        if (++sInstanceCount == 1) {
+            WebLayerAccessibilityUtil.get().addObserver(sAccessibilityObserver);
+        }
+
         mTab = tab;
         mTab.getWebContents().addObserver(mWebContentsObserver);
 
@@ -304,6 +321,11 @@ public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Con
 
     public void destroy() {
         mTab.getWebContents().removeObserver(mWebContentsObserver);
+
+        if (--sInstanceCount == 0) {
+            WebLayerAccessibilityUtil.get().removeObserver(sAccessibilityObserver);
+        }
+
         if (mInfoBarContainerView != null) destroyContainerView();
         if (mNativeInfoBarContainer != 0) {
             InfoBarContainerJni.get().destroy(mNativeInfoBarContainer, InfoBarContainer.this);

weblayer/browser/java/org/chromium/weblayer_private/InfoBarContainerView.java

@@ -106,7 +106,8 @@ public class InfoBarContainerView extends SwipableOverlayView {
 
     // SwipableOverlayView implementation.
     @Override
-    protected boolean isAllowedToAutoHide() {
+    @VisibleForTesting
+    public boolean isAllowedToAutoHide() {
         return sIsAllowedToAutoHide;
     }
 

weblayer/browser/java/org/chromium/weblayer_private/TabImpl.java

@@ -887,6 +887,11 @@ public final class TabImpl extends ITab.Stub implements LoginPrompt.Observer {
         return (mBrowser.getActiveTab() == this) ? mBrowser.getViewController() : null;
     }
 
+    @VisibleForTesting
+    public boolean canInfoBarContainerScrollForTesting() {
+        return mInfoBarContainer.getContainerViewForTesting().isAllowedToAutoHide();
+    }
+
     @NativeMethods
     interface Natives {
         TabImpl fromWebContents(WebContents webContents);

weblayer/browser/java/org/chromium/weblayer_private/test/TestWebLayerImpl.java

@@ -157,4 +157,9 @@ public final class TestWebLayerImpl extends ITestWebLayer.Stub {
                 long tabImpl, int top, int bottom, Runnable runnable);
         void setIgnoreMissingKeyForTranslateManager(boolean ignore);
     }
+
+    @Override
+    public boolean canInfoBarContainerScroll(ITab tab) {
+        return ((TabImpl) tab).canInfoBarContainerScrollForTesting();
+    }
 }

weblayer/browser/java/org/chromium/weblayer_private/test_interfaces/ITestWebLayer.aidl

@@ -42,4 +42,6 @@ interface ITestWebLayer {
 
   void setIgnoreMissingKeyForTranslateManager(in boolean ignore) = 12;
   void forceNetworkConnectivityState(in boolean networkAvailable) = 13;
+
+  boolean canInfoBarContainerScroll(in ITab tab) = 14;
 }

weblayer/public/javatestutil/org/chromium/weblayer/TestWebLayer.java

@@ -110,4 +110,8 @@ public final class TestWebLayer {
     public void forceNetworkConnectivityState(boolean networkAvailable) throws RemoteException {
         mITestWebLayer.forceNetworkConnectivityState(networkAvailable);
     }
+
+    public boolean canInfoBarContainerScroll(Tab tab) throws RemoteException {
+        return mITestWebLayer.canInfoBarContainerScroll(tab.getITab());
+    }
 }