Only acquire title if Tab is initialized in AccessibilityTabModel

We should only acquire Title if the Tab is initialized. Now with
some attributes such as Title being moved to UserData objects
we enforce this.

Bug: 1114564
Change-Id: I876603c4126a24a1e6e8579f90cf7beb32e9871b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352511Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797330}

chrome/android/java/src/org/chromium/chrome/browser/accessibility_tab_switcher/AccessibilityTabModelListItem.java

@@ -304,7 +304,7 @@ public class AccessibilityTabModelListItem extends FrameLayout implements OnClic
     private void updateTabText() {
         String title = null;
         String url = null;
-        if (mTab != null) {
+        if (mTab != null && mTab.isInitialized()) {
             title = mTab.getTitle();
             url = mTab.getUrlString();
             if (TextUtils.isEmpty(title)) title = url;