[Sync] Fix Session's handling of windows.

chrome/browser/sync/glue/synced_session.h

Index: chrome/browser/sync/glue/synced_session.h
diff --git a/chrome/browser/sync/glue/synced_session.h b/chrome/browser/sync/glue/synced_session.h
index 00f956b9be79c900ec746fa40be37e7f9420a764..52e642c5eb79f508bd9d4c770a1a01f77da8f927 100644
--- a/chrome/browser/sync/glue/synced_session.h
+++ b/chrome/browser/sync/glue/synced_session.h
@@ -6,8 +6,10 @@
 #define CHROME_BROWSER_SYNC_GLUE_SYNCED_SESSION_H_
 #pragma once
 
+#include <map>
 #include <string>
-#include <vector>
+
+#include "chrome/browser/sessions/session_id.h"
 
 struct SessionWindow;
 
@@ -17,6 +19,8 @@ namespace browser_sync {
 // 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,
@@ -34,8 +38,16 @@ struct SyncedSession {
   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);
 };
 
 }  // namespace browser_sync