Don't acquire URL on uninitialized Tab in LocationBarModel

We now enforce that tab attributes cannot be acquired after
Tab#destroy() has been called. This part of the code contains
an invalid assumption that the tab is ininitialized when calling
getUrlString().

Bug: 1117396
Change-Id: I54cc4feb317d302db04538cf006ac82cfaa7e730
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410921Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Commit-Queue: David Maunder <davidjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807100}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/LocationBarModel.java

@@ -131,7 +131,7 @@ public class LocationBarModel implements ToolbarDataProvider, ToolbarCommonPrope
         }
 
         // TODO(yusufo) : Consider using this for all calls from getTab() for accessing url.
-        if (!hasTab()) return "";
+        if (!hasTab() || !getTab().isInitialized()) return "";
 
         // Tab.getUrl() returns empty string if it does not have a URL.
         return getTab().getUrlString().trim();