[Sync] Add histograms for cookie jar state on Sessions commit

components/sync_driver/glue/sync_backend_host_core.h

 // Copyright 2013 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_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_
 #define COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 244 matching lines @@
 
   // Tell the sync manager to persist its state by writing to disk.
   // Called on the sync thread, both by a timer and, on Android, when the
   // application is backgrounded.
   void SaveChanges();
 
   void DoClearServerData(
       const syncer::SyncManager::ClearServerDataCallback& frontend_callback);
 
   // Notify the syncer that the cookie jar has changed.
-  void DoOnCookieJarChanged(bool account_mismatch);
+  void DoOnCookieJarChanged(bool account_mismatch, bool empty_jar);
 
  private:
   friend class base::RefCountedThreadSafe<SyncBackendHostCore>;
   friend class SyncBackendHostForProfileSyncTest;
 
   ~SyncBackendHostCore() override;
 
   // Invoked when initialization of syncapi is complete and we can start
   // our timer.
   // This must be called from the thread on which SaveChanges is intended to
@@ skipping 59 matching lines @@
   std::map<syncer::ModelType, int64_t> last_invalidation_versions_;
 
   base::WeakPtrFactory<SyncBackendHostCore> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostCore);
 };
 
 }  // namespace browser_sync
 
 #endif  // COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_