[WebLayer] Reset infobar container visibility on navigation

This CL has InfoBarContainer reset itself to being visible when a
navigation commits. This is an adaptation of Chrome's behavior: in
Chrome some features hide the infobar container, which should always be
undone on navigation. While no feature in WebLayer yet does this, it is
good to have this defensive behavior in place so that any such added
features don't end up inadvertently hiding the infobar container
"forever" in a given tab.

Bug: 1093846
Change-Id: I9ead10a1be0b670d8b3f14c195657e60a4a43f20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2254022
Commit-Queue: Colin Blundell <blundell@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781743}

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

@@ -137,4 +137,22 @@ public class InfoBarTest {
 
         Assert.assertEquals(infoBarContainerView.getParent(), null);
     }
+
+    @Test
+    @SmallTest
+    /**
+     * Tests that if the infobar container view is hidden, its visibility is restored on navigation.
+     *
+     */
+    public void testVisibilityRestoredOnNavigation() throws Exception {
+        View infoBarContainerView = getInfoBarContainerView();
+        Assert.assertEquals(infoBarContainerView.getVisibility(), View.VISIBLE);
+
+        TestThreadUtils.runOnUiThreadBlocking(
+                () -> { infoBarContainerView.setVisibility(View.GONE); });
+        Assert.assertEquals(infoBarContainerView.getVisibility(), View.GONE);
+
+        mActivityTestRule.navigateAndWait("about:blank");
+        Assert.assertEquals(infoBarContainerView.getVisibility(), View.VISIBLE);
+    }
 }

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

@@ -16,7 +16,9 @@ import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.NativeMethods;
 import org.chromium.chrome.browser.infobar.InfoBarIdentifier;
+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 java.util.ArrayList;
@@ -87,8 +89,21 @@ public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Con
         void onInfoBarContainerShownRatioChanged(InfoBarContainer container, float shownRatio);
     }
 
-    // TODO(crbug.com/1025620): Observe WebContents to reset the state of the InfoBarContainer when
-    // the user navigates, a la //chrome's observing of Tab here.
+    /**
+     * Resets the visibility of the InfoBarContainer when the user navigates, following Chrome's
+     * behavior. In particular in Chrome some features hide the infobar container. This hiding is
+     * always on a per-URL basis that should be undone on navigation. While no feature in WebLayer
+     * yet does this, we put this * defensive behavior in place so that any such added features
+     * don't end up inadvertently hiding the infobar container "forever" in a given tab.
+     */
+    private final WebContentsObserver mWebContentsObserver = new WebContentsObserver() {
+        @Override
+        public void didFinishNavigation(NavigationHandle navigation) {
+            if (navigation.hasCommitted() && navigation.isInMainFrame()) {
+                setHidden(false);
+            }
+        }
+    };
 
     public void onTabDidGainActive() {
         initializeContainerView(mTab.getBrowser().getContext());
@@ -152,6 +167,7 @@ public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Con
 
     InfoBarContainer(TabImpl tab) {
         mTab = tab;
+        mTab.getWebContents().addObserver(mWebContentsObserver);
 
         // Chromium's InfoBarContainer may add an InfoBar immediately during this initialization
         // call, so make sure everything in the InfoBarContainer is completely ready beforehand.
@@ -287,6 +303,7 @@ public class InfoBarContainer implements KeyboardVisibilityListener, InfoBar.Con
     }
 
     public void destroy() {
+        mTab.getWebContents().removeObserver(mWebContentsObserver);
         if (mInfoBarContainerView != null) destroyContainerView();
         if (mNativeInfoBarContainer != 0) {
             InfoBarContainerJni.get().destroy(mNativeInfoBarContainer, InfoBarContainer.this);