[Chromeshine] Prevent crash when accessing SuspendedTab for destroyed tab

Bug: b/148339489
Change-Id: I1714f3439c6d88d764b8e894add7fd93eeed2baf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032422
Commit-Queue: Patrick Noland <pnoland@chromium.org>
Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737413}

chrome/android/java/src/org/chromium/chrome/browser/usage_stats/PageViewObserver.java

@@ -125,6 +125,7 @@ public class PageViewObserver {
 
     /** Notify PageViewObserver that {@code fqdn} was just suspended or un-suspended. */
     public void notifySiteSuspensionChanged(String fqdn, boolean isSuspended) {
+        if (mCurrentTab != null && !mCurrentTab.isInitialized()) return;
         SuspendedTab suspendedTab = SuspendedTab.from(mCurrentTab);
         if (fqdn.equals(mLastFqdn) || fqdn.equals(suspendedTab.getFqdn())) {
             if (checkSuspendedTabState(isSuspended, fqdn)) {

chrome/android/java/src/org/chromium/chrome/browser/usage_stats/SuspendedTab.java

@@ -48,7 +48,12 @@ public class SuspendedTab extends EmptyTabObserver implements UserData {
         return suspendedTab != null && suspendedTab.isShowing();
     }
 
+    /**
+     * @return The SuspendedTab instance for the given Tab object. This can never return null, but
+     *         is not safe to call if the tab has been destroyed.
+     */
     public static SuspendedTab from(Tab tab) {
+        assert tab.isInitialized();
         SuspendedTab suspendedTab = get(tab);
         if (suspendedTab == null) {
             suspendedTab = tab.getUserDataHost().setUserData(USER_DATA_KEY, new SuspendedTab(tab));

chrome/android/junit/src/org/chromium/chrome/browser/usage_stats/PageViewObserverTest.java

@@ -80,6 +80,7 @@ public final class PageViewObserverTest {
     private TabObserver mTabObserver;
     private UserDataHost mUserDataHost;
     private UserDataHost mUserDataHostTab2;
+    private UserDataHost mDestroyedUserDataHost;
 
     @Before
     public void setUp() {
@@ -87,10 +88,14 @@ public final class PageViewObserverTest {
 
         mUserDataHost = new UserDataHost();
         mUserDataHostTab2 = new UserDataHost();
+        mDestroyedUserDataHost = new UserDataHost();
+        mDestroyedUserDataHost.destroy();
 
         doReturn(false).when(mTab).isIncognito();
         doReturn(null).when(mTab).getUrl();
         doReturn(mChromeActivity).when(mTab).getActivity();
+        doReturn(true).when(mTab).isInitialized();
+        doReturn(true).when(mTab2).isInitialized();
         doReturn(Arrays.asList(mTabModel)).when(mTabModelSelector).getModels();
         doReturn(mTab).when(mTabModelSelector).getCurrentTab();
         doReturn(mUserDataHost).when(mTab).getUserDataHost();
@@ -429,6 +434,16 @@ public final class PageViewObserverTest {
         verify(mEventTracker, times(1)).addWebsiteEvent(argThat(isStartEvent(STARTING_FQDN)));
     }
 
+    @Test
+    public void eagerSuspension_destroyedTab() {
+        PageViewObserver observer = createPageViewObserver();
+        updateUrl(mTab, STARTING_URL);
+
+        doReturn(mDestroyedUserDataHost).when(mTab).getUserDataHost();
+        doReturn(false).when(mTab).isInitialized();
+        observer.notifySiteSuspensionChanged(STARTING_FQDN, true);
+    }
+
     private PageViewObserver createPageViewObserver() {
         PageViewObserver observer = new PageViewObserver(
                 mActivity, mTabModelSelector, mEventTracker, mTokenTracker, mSuspensionTracker);