[Sync] Store the past 10 traffic records in memory.

sync/sessions/sync_session_context.h

 // Copyright (c) 2012 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.
 
 // SyncSessionContext encapsulates the contextual information and engine
 // components specific to a SyncSession. A context is accessible via
 // a SyncSession so that session SyncerCommands and parts of the engine have
 // a convenient way to access other parts. In this way it can be thought of as
 // the surrounding environment for the SyncSession. The components of this
 // environment are either valid or not valid for the entire context lifetime,
 // or they are valid for explicitly scoped periods of time by using Scoped
 // installation utilities found below. This means that the context assumes no
 // ownership whatsoever of any object that was not created by the context
 // itself.
 //
 // It can only be used from the SyncerThread.
 
 #ifndef SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_
 #define SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_
 #pragma once
 
 #include <map>
+#include <queue>
 #include <string>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "sync/engine/model_safe_worker.h"
 #include "sync/engine/syncer_types.h"
+#include "sync/engine/traffic_logger.h"
 #include "sync/sessions/debug_info_getter.h"
 
 namespace syncable {
 class Directory;
 }
 
 namespace browser_sync {
 
 class ConflictResolver;
 class ExtensionsActivityMonitor;
@@ skipping 76 matching lines @@
                                  const base::TimeTicks& time);
 
   // This prunes the |unthrottle_time_| map based on the |time| passed in. This
   // is called by syncer at the SYNCER_BEGIN stage.
   void PruneUnthrottledTypes(const base::TimeTicks& time);
 
   // This returns the list of currently throttled types. Unless server returns
   // new throttled types this will remain constant through out the sync cycle.
   syncable::ModelTypeSet GetThrottledTypes() const;
 
+  std::queue<TrafficRecord>* traffic_recorder() {
+    return &traffic_recorder_;
+  }
+
  private:
   typedef std::map<syncable::ModelType, base::TimeTicks> UnthrottleTimes;
 
   FRIEND_TEST_ALL_PREFIXES(SyncSessionContextTest, AddUnthrottleTimeTest);
   FRIEND_TEST_ALL_PREFIXES(SyncSessionContextTest,
                            GetCurrentlyThrottledTypesTest);
 
   // Rather than force clients to set and null-out various context members, we
   // extend our encapsulation boundary to scoped helpers that take care of this
   // once they are allocated. See definitions of these below.
@@ skipping 34 matching lines @@
   scoped_ptr<sessions::SyncSessionSnapshot> previous_session_snapshot_;
 
   // We use this to get debug info to send to the server for debugging
   // client behavior on server side.
   DebugInfoGetter* const debug_info_getter_;
 
   // This is a map from throttled data types to the time at which they can be
   // unthrottled.
   UnthrottleTimes unthrottle_times_;
 
+  std::queue<browser_sync::TrafficRecord> traffic_recorder_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncSessionContext);
 };
 
 // Installs a ConflictResolver to a given session context for the lifetime of
 // the ScopedSessionContextConflictResolver.  There should never be more than
 // one ConflictResolver in the system, so it is an error to use this if the
 // context already has a resolver.
 class ScopedSessionContextConflictResolver {
  public:
   // Note: |context| and |resolver| should outlive |this|.
   ScopedSessionContextConflictResolver(SyncSessionContext* context,
                                        ConflictResolver* resolver)
       : context_(context), resolver_(resolver) {
     DCHECK(NULL == context->resolver_);
     context->resolver_ = resolver;
   }
   ~ScopedSessionContextConflictResolver() {
     context_->resolver_ = NULL;
    }
  private:
   SyncSessionContext* context_;
   ConflictResolver* resolver_;
   DISALLOW_COPY_AND_ASSIGN(ScopedSessionContextConflictResolver);
 };
 
 }  // namespace sessions
 }  // namespace browser_sync
 
 #endif  // SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_