[Sync] Fix namespaces for the sync_sessions component.

components/sync_sessions/sync_sessions_metrics.cc

 // Copyright 2016 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.
 
 #include "components/sync_sessions/sync_sessions_metrics.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/time/time.h"
 #include "components/sessions/core/session_types.h"
 #include "components/sync_sessions/sessions_sync_manager.h"
 #include "components/sync_sessions/synced_session.h"
 
 namespace sync_sessions {
 
 // static
 void SyncSessionsMetrics::RecordYoungestForeignTabAgeOnNTP(
-    browser_sync::SessionsSyncManager* sessions_sync_manager) {
+    SessionsSyncManager* sessions_sync_manager) {
   if (sessions_sync_manager != NULL) {
-    std::vector<const sync_driver::SyncedSession*> foreign_sessions;
+    std::vector<const SyncedSession*> foreign_sessions;
     sessions_sync_manager->GetAllForeignSessions(&foreign_sessions);
     base::Time best(MaxTabTimestamp(foreign_sessions));
     base::Time now(base::Time::Now());
     // Don't emit metrics if the foreign tab is timestamped in the future. While
     // the timestamp is set on a different machine, and we may lose some
     // fraction of metrics to clock skew, we don't want the potential to have
     // bad machines with clocks many hours off causing lots of seemingly 0
     // second entries.
     if (base::Time::UnixEpoch() < best && best <= now) {
       UMA_HISTOGRAM_CUSTOM_COUNTS(
           "Sync.YoungestForeignTabAgeOnNTP", (now - best).InSeconds(), 1,
           base::TimeDelta::FromDays(14).InSeconds(), 100);
     }
   }
 }
 
 // static
 base::Time SyncSessionsMetrics::MaxTabTimestamp(
-    const std::vector<const sync_driver::SyncedSession*>& sessions) {
+    const std::vector<const SyncedSession*>& sessions) {
   // While Sessions are ordered by recency, windows and tabs are not. Because
   // the timestamp of sessions are updated when windows/tabs are removed, we
   // only need to search until all the remaining sessions are older than the
   // most recent tab we've found so far.
   base::Time best(base::Time::UnixEpoch());
-  for (const sync_driver::SyncedSession* session : sessions) {
+  for (const SyncedSession* session : sessions) {
     if (session->modified_time < best) {
       break;
     }
     for (const std::pair<const SessionID::id_type, sessions::SessionWindow*>&
              key_value : session->windows) {
       for (const sessions::SessionTab* tab : key_value.second->tabs) {
         best = std::max(best, tab->timestamp);
       }
     }
   }
   return best;
 }
 
 }  // namespace sync_sessions