Fix tab insertion position after moving tab or nesting openers

chrome/browser/ui/tabs/tab_strip_model.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/tabs/tab_strip_model.h"
 
 #include <algorithm>
 #include <map>
+#include <set>
 #include <string>
 
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/extensions/tab_helper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/tab_contents/core_tab_helper.h"
@@ skipping 572 matching lines @@
       return i;
   }
   return kNoTab;
 }
 
 int TabStripModel::GetIndexOfLastWebContentsOpenedBy(const WebContents* opener,
                                                      int start_index) const {
   DCHECK(opener);
   DCHECK(ContainsIndex(start_index));
 
-  for (int i = contents_data_.size() - 1; i > start_index; --i) {
-    if (contents_data_[i]->opener() == opener)
-      return i;
+  std::set<const WebContents*> opener_and_descendants;
+  opener_and_descendants.insert(opener);
+  int last_index = kNoTab;
+
+  for (int i = start_index + 1; i < count(); ++i) {
+    // Test opened by transitively, i.e. include tabs opened by tabs opened by
+    // opener, etc. Stop when we find the first non-descendant.
+    if (!opener_and_descendants.count(contents_data_[i]->opener()))
+      break;
+    opener_and_descendants.insert(contents_data_[i]->web_contents());
+    last_index = i;
   }
-  return kNoTab;
+  return last_index;
 }
 
 void TabStripModel::TabNavigating(WebContents* contents,
                                   ui::PageTransition transition) {
   if (ShouldForgetOpenersForTransition(transition)) {
     // Don't forget the openers if this tab is a New Tab page opened at the
     // end of the TabStrip (e.g. by pressing Ctrl+T). Give the user one
     // navigation of one of these transition types before resetting the
     // opener relationships (this allows for the use case of opening a new
     // tab to do a quick look-up of something while viewing a tab earlier in
@@ skipping 813 matching lines @@
 void TabStripModel::ForgetOpenersAndGroupsReferencing(
     const WebContents* tab) {
   for (WebContentsDataVector::const_iterator i = contents_data_.begin();
        i != contents_data_.end(); ++i) {
     if ((*i)->group() == tab)
       (*i)->set_group(NULL);
     if ((*i)->opener() == tab)
       (*i)->set_opener(NULL);
   }
 }