[Sync] Fix Session's handling of windows.

chrome/browser/sync/glue/synced_session.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_SYNC_GLUE_SYNCED_SESSION_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNCED_SESSION_H_
 #pragma once
 
+#include <map>
 #include <string>
-#include <vector>
 
+#include "chrome/browser/sessions/session_id.h"
+
+struct SessionTab;
 struct SessionWindow;
 
 namespace browser_sync {
 
 // Defines a synced session for use by session sync. A synced session is a
 // list of windows along with a unique session identifer (tag) and meta-data
 // about the device being synced.
 struct SyncedSession {
+  typedef std::map<SessionID::id_type, SessionWindow*> SyncedWindowMap;
+
   // The type of device.
   enum DeviceType {
     TYPE_UNSET = 0,
     TYPE_WIN = 1,
     TYPE_MACOSX = 2,
     TYPE_LINUX = 3,
     TYPE_CHROMEOS = 4,
     TYPE_OTHER = 5
   };
 
   SyncedSession();
   ~SyncedSession();
 
   // Unique tag for each session.
   std::string session_tag;
   // User-visible name
   std::string session_name;
+
+  // Type of device this session is from.
   DeviceType device_type;
-  std::vector<SessionWindow*> windows;
+
+  // Map of windows that make up this session. Windowws are owned by the session
+  // itself and free'd on destruction.
+  SyncedWindowMap windows;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SyncedSession);
 };
 
+// Control which foreign tabs we're interested in syncing/displaying. Checks
+// that the tab has navigations and is not a new tab (url == NTP).
+// Note: A new tab page with back/forward history is valid.
+bool IsValidSessionTab(const SessionTab& tab);
+
+// Checks whether the window has tabs to sync. If no tabs to sync, it returns
+// true, false otherwise.
+bool SessionWindowHasNoTabsToSync(const SessionWindow& window);
+
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNCED_SESSION_H_