Fix crash when following a link opening a new tab/window.

chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h"
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "components/sessions/content/content_serialized_navigation_builder.h"
@@ skipping 67 matching lines @@
 int TabContentsSyncedTabDelegate::GetCurrentEntryIndex() const {
   return web_contents_->GetController().GetCurrentEntryIndex();
 }
 
 int TabContentsSyncedTabDelegate::GetEntryCount() const {
   return web_contents_->GetController().GetEntryCount();
 }
 
 GURL TabContentsSyncedTabDelegate::GetVirtualURLAtIndex(int i) const {
   NavigationEntry* entry = GetPossiblyPendingEntryAtIndex(web_contents_, i);
-  return entry->GetVirtualURL();
+  return entry ? entry->GetVirtualURL() : GURL();
 }
 
 GURL TabContentsSyncedTabDelegate::GetFaviconURLAtIndex(int i) const {
   NavigationEntry* entry = GetPossiblyPendingEntryAtIndex(web_contents_, i);
   return (entry->GetFavicon().valid ? entry->GetFavicon().url : GURL());
 }
 
 ui::PageTransition TabContentsSyncedTabDelegate::GetTransitionAtIndex(
     int i) const {
   NavigationEntry* entry = GetPossiblyPendingEntryAtIndex(web_contents_, i);
@@ skipping 56 matching lines @@
   for (int i = 0; i < entry_count; ++i) {
     const GURL& virtual_url = GetVirtualURLAtIndex(i);
     if (!virtual_url.is_valid())
       continue;
 
     if (sessions_client->ShouldSyncURL(virtual_url))
       return true;
   }
   return false;
 }