[Sync] Restore previous session if no tabbed windows present

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
index 5623df08703de7d5b766f1edca9a398e92bcbe10..cb37e550e89cb3c1048e49bdd252cbb966659405 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
@@ -88,6 +88,7 @@ import org.chromium.chrome.browser.util.FeatureUtilities;
 import org.chromium.components.dom_distiller.core.DomDistillerUrlUtils;
 import org.chromium.components.navigation_interception.InterceptNavigationDelegate;
 import org.chromium.components.security_state.ConnectionSecurityLevel;
+import org.chromium.components.sync.SyncConstants;
 import org.chromium.content.browser.ChildProcessLauncher;
 import org.chromium.content.browser.ContentView;
 import org.chromium.content.browser.ContentViewClient;
@@ -177,7 +178,7 @@ public class Tab
     private SwipeRefreshHandler mSwipeRefreshHandler;
 
     /** The sync id of the Tab if session sync is enabled. */
-    private int mSyncId;
+    private int mSyncId = SyncConstants.INVALID_TAB_NODE_ID;
 
     /** {@link ContentViewCore} showing the current page, or {@code null} if the tab is frozen. */
     private ContentViewCore mContentViewCore;