Take 2 at browser_sync::ExtensionsActivityMonitor....

chrome/browser/sync/engine/syncer.h

 // Copyright (c) 2009 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 entry.
 
 #ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_
 #define CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_
 
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
 #include "base/time.h"
 #include "chrome/browser/sync/engine/client_command_channel.h"
 #include "chrome/browser/sync/engine/conflict_resolver.h"
 #include "chrome/browser/sync/engine/syncer_types.h"
 #include "chrome/browser/sync/engine/syncproto.h"
 #include "chrome/browser/sync/syncable/directory_event.h"
 #include "chrome/browser/sync/util/event_sys-inl.h"
 #include "chrome/browser/sync/util/event_sys.h"
+#include "chrome/browser/sync/util/extensions_activity_monitor.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"  // For FRIEND_TEST
 
 namespace syncable {
 class Directory;
 class DirectoryManager;
 class Entry;
 class Id;
 class MutableEntry;
 class WriteTransaction;
 }  // namespace syncable
@@ skipping 141 matching lines @@
 
   scoped_ptr<SyncerEventChannel> syncer_event_channel_;
   scoped_ptr<ShutdownChannel> shutdown_channel_;
   ClientCommandChannel* command_channel_;
 
   // A worker capable of processing work closures on a thread that is
   // guaranteed to be safe for model modifications. This is created and owned
   // by the SyncerThread that created us.
   ModelSafeWorker* model_safe_worker_;
 
+  // We use this to stuff extensions activity into CommitMessages so the server
+  // can correlate commit traffic with extension-related bookmark mutations.
+  ExtensionsActivityMonitor* extensions_monitor_;
+
   // The source of the last nudge.
   sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE updates_source_;
 
   // True only if the notification channel is authorized and open.
   bool notifications_enabled_;
 
   // A callback hook used in unittests to simulate changes between conflict set
   // building and conflict resolution.
   TestCallbackFunction pre_conflict_resolution_function_;
 
@@ skipping 35 matching lines @@
 void CopyServerFields(syncable::Entry* src, syncable::MutableEntry* dest);
 void ClearServerData(syncable::MutableEntry* entry);
 
 // Get update contents as a string. Intended for logging, and intended
 // to have a smaller footprint than the protobuf's built-in pretty printer.
 std::string SyncEntityDebugString(const sync_pb::SyncEntity& entry);
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_