Clear session-only data when all browser windows are closed.

chrome/browser/sessions/session_service.cc

Index: chrome/browser/sessions/session_service.cc
diff --git a/chrome/browser/sessions/session_service.cc b/chrome/browser/sessions/session_service.cc
index 8af213819455fd1c504812e703144914eaef1338..d7fdb81b54c54b62c6f035bd37d6328577a61f6d 100644
--- a/chrome/browser/sessions/session_service.cc
+++ b/chrome/browser/sessions/session_service.cc
@@ -16,12 +16,15 @@
 #include "base/metrics/histogram.h"
 #include "base/pickle.h"
 #include "base/threading/thread.h"
+#include "chrome/browser/background/background_mode_manager.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/tab_helper.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_backend.h"
 #include "chrome/browser/sessions/session_command.h"
+#include "chrome/browser/sessions/session_data_deleter.h"
 #include "chrome/browser/sessions/session_restore.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/browser/sessions/session_types.h"
@@ -338,6 +341,12 @@ void SessionService::WindowClosed(const SessionID& window_id) {
     else
       ScheduleCommand(CreateWindowClosedCommand(window_id.id()));
   }
+#if !defined(OS_MACOSX) && !defined(OS_CHROMEOS)
+  if (!has_open_trackable_browsers_ &&
+      !g_browser_process->background_mode_manager()->IsBackgroundModeActive()) {
+    DeleteSessionOnlyData(profile());
+  }
+#endif
 }
 
 void SessionService::SetWindowType(const SessionID& window_id,