Relanding in-progress download bug fix

chrome/browser/tabs/tab_strip_model.cc

 // Copyright (c) 2006-2008 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/tabs/tab_strip_model.h"
 
 #include <algorithm>
 
 #include "base/string_util.h"
 #include "chrome/browser/metrics/user_metrics.h"
@@ skipping 497 matching lines @@
 
 bool TabStripModel::IsNewTabAtEndOfTabStrip(TabContents* contents) const {
   return LowerCaseEqualsASCII(contents->GetURL().spec(),
                               chrome::kChromeUINewTabURL) &&
       contents == GetContentsAt(count() - 1) &&
       contents->controller().entry_count() == 1;
 }
 
 bool TabStripModel::InternalCloseTabContentsAt(int index,
                                                bool create_historical_tab) {
+  if (!delegate_->CanCloseContentsAt(index))
+    return false;
+
   TabContents* detached_contents = GetContentsAt(index);
 
   if (delegate_->RunUnloadListenerBeforeClosing(detached_contents))
     return false;
 
   // TODO: Now that we know the tab has no unload/beforeunload listeners,
   // we should be able to do a fast shutdown of the RenderViewProcess.
   // Make sure that we actually do.
 
   FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
@@ skipping 37 matching lines @@
   int index = GetIndexOfTabContents(contents);
   contents_data_.at(index)->opener = &opener->controller();
 }
 
 // static
 bool TabStripModel::OpenerMatches(const TabContentsData* data,
                                   const NavigationController* opener,
                                   bool use_group) {
   return data->opener == opener || (use_group && data->group == opener);
 }