Prevent tabs sync during browser shutdown.

components/sync_sessions/local_session_event_router.h

 // Copyright 2015 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 COMPONENTS_SYNC_SESSIONS_LOCAL_SESSION_EVENT_ROUTER_H_
 #define COMPONENTS_SYNC_SESSIONS_LOCAL_SESSION_EVENT_ROUTER_H_
 
 #include <set>
 
 #include "base/macros.h"
@@ skipping 17 matching lines @@
 
   // A local navigation occurred that triggered updates to favicon data for
   // each page URL in |page_urls| (e.g. http://www.google.com) and the icon URL
   // |icon_url| (e.g. http://www.google.com/favicon.ico). This is routed through
   // Sessions Sync so that we can filter (exclude) favicon updates for pages
   // that aren't currently part of the set of local open tabs, and pass relevant
   // updates on to FaviconCache for out-of-band favicon syncing.
   virtual void OnFaviconsChanged(const std::set<GURL>& page_urls,
                                  const GURL& icon_url) = 0;
 
+  // A flag set when browsers are closing, so we shouldn't send tabs
+  // closing events to sync server. Tabs will be restored on the next browser
+  // start.
+  virtual void SetAllBrowsersClosing(bool browsers_closing) = 0;
+
  protected:
   LocalSessionEventHandler() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LocalSessionEventHandler);
 };
 
 // The LocalSessionEventRouter is responsible for hooking itself up to various
 // notification sources in the browser process and forwarding relevant
 // events to a handler as defined in the LocalSessionEventHandler contract.
 class LocalSessionEventRouter {
  public:
   virtual ~LocalSessionEventRouter() {}
   virtual void StartRoutingTo(LocalSessionEventHandler* handler) = 0;
   virtual void Stop() = 0;
 
  protected:
   LocalSessionEventRouter() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LocalSessionEventRouter);
 };
 
 }  // namespace sync_sessions
 
 #endif  // COMPONENTS_SYNC_SESSIONS_LOCAL_SESSION_EVENT_ROUTER_H_