Don't acquire title on uninitialized Tab in TabPrinter

We no longer allow tab attributes to be acquired after
tab#destroy(). This has unveiled a number of places in the codebase
where invalid assumptions have been made. This patch fixes
one of them in TabPrinter.

Bug: 1117396
Change-Id: I7657824663b28eeaaf3f98a40d243a9d7bd6d167
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409675Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: David Maunder <davidjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807031}

chrome/android/java/src/org/chromium/chrome/browser/printing/TabPrinter.java

@@ -55,7 +55,7 @@ public class TabPrinter implements Printable {
     @Override
     public String getTitle() {
         Tab tab = mTab.get();
-        if (tab == null) return mDefaultTitle;
+        if (tab == null || !tab.isInitialized()) return mDefaultTitle;
 
         String title = tab.getTitle();
         if (!TextUtils.isEmpty(title)) return title;