Fix acquisition of root id on PseudoTab

Following moving rootId to a UserData object
(CriticalPersistedTabData) it is now necessary to check if
the Tab is destroyed before attempting to access root id
from the CriticalPersistedTabData object. Previously root
id was available right up until the object no longer
existed.

Bug: 1097009
Change-Id: I78ca61cdff2ccc3275a48425a76514790c59daac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2257500Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: David Maunder <davidjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781382}

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/pseudotab/PseudoTab.java

@@ -180,7 +180,7 @@ public class PseudoTab {
      * @return The root ID
      */
     public int getRootId() {
-        if (mTab != null && mTab.get() != null) {
+        if (mTab != null && mTab.get() != null && mTab.get().isInitialized()) {
             return CriticalPersistedTabData.from(mTab.get()).getRootId();
         }
         assert mTabId != null;

chrome/android/features/tab_ui/junit/src/org/chromium/chrome/browser/tasks/pseudotab/PseudoTabUnitTest.java

@@ -20,6 +20,7 @@ import org.mockito.MockitoAnnotations;
 
 import org.chromium.base.test.BaseRobolectricTestRunner;
 import org.chromium.chrome.browser.flags.ChromeFeatureList;
+import org.chromium.chrome.browser.tab.MockTab;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabImpl;
 import org.chromium.chrome.browser.tab.state.CriticalPersistedTabData;
@@ -52,6 +53,7 @@ public class PseudoTabUnitTest {
     private static final int TAB1_ID = 456;
     private static final int TAB2_ID = 789;
     private static final int TAB3_ID = 123;
+    private static final int TAB4_ID = 159;
 
     @Mock
     TabModelFilter mTabModelFilter;
@@ -423,4 +425,14 @@ public class PseudoTabUnitTest {
         Assert.assertEquals(TAB2_ID, related.get(1).getId());
     }
 
+    @Test
+    public void testTabDestroyed() {
+        Tab tab = new MockTab(TAB4_ID, false);
+        PseudoTab pseudoTab = PseudoTab.fromTab(tab);
+        tab.destroy();
+        // Root ID was not set. Without the isInitialized() check,
+        // pseudoTab.getRootId() would crash here with
+        // UnsupportedOperationException
+        Assert.assertEquals(Tab.INVALID_TAB_ID, pseudoTab.getRootId());
+    }
 }

chrome/android/features/tab_ui/junit/src/org/chromium/chrome/browser/tasks/tab_management/TabUiUnitTestUtils.java

@@ -21,7 +21,9 @@ import org.chromium.url.GURL;
 @SuppressWarnings("ResultOfMethodCallIgnored")
 public class TabUiUnitTestUtils {
     public static TabImpl prepareTab() {
-        return mock(TabImpl.class);
+        TabImpl tab = mock(TabImpl.class);
+        doReturn(true).when(tab).isInitialized();
+        return tab;
     }
 
     public static TabImpl prepareTab(int tabId) {