Field trial removing tiles from NTP if URL is already open - for 1993 clients

chrome/browser/ui/tabs/tab_strip_model_utils.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_utils.h"
 
+#include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "content/public/browser/web_contents.h"
 
 namespace chrome {
 
 int IndexOfFirstBlockedTab(const TabStripModel* model) {
   DCHECK(model);
   for (int i = 0; i < model->count(); ++i) {
     if (model->IsTabBlocked(i))
       return i;
   }
   // No blocked tabs.
   return model->count();
 }
 
+// Creates a set containing the canonical URLs of the currently open tabs.

[Alexei Svitkine (slow), 2013/07/24 18:37:36]

No need for a comment here, given that you already have one in the header file.

[annark1, 2013/07/24 20:43:31]

Done.

+void GetOpenUrls(const TabStripModel& tabs,
+                 const history::TopSites& top_sites,
+                 std::set<std::string>* urls) {
+  for (int i = 0; i < tabs.count(); ++i) {
+    content::WebContents* web_contents = tabs.GetWebContentsAt(i);
+    if (web_contents)
+      urls->insert(top_sites.GetCanonicalURLString(web_contents->GetURL()));
+  }
+}
+
 }  // namespace chrome