[Sync] Fix namespaces for the sync_sessions component.

components/sync_sessions/sync_sessions_metrics.cc

Index: components/sync_sessions/sync_sessions_metrics.cc
diff --git a/components/sync_sessions/sync_sessions_metrics.cc b/components/sync_sessions/sync_sessions_metrics.cc
index fb037975b182eeacade4229c54a6ef751d38f128..7f9378b36ab9b73d7e6cf4f5ba038d7ea11703cf 100644
--- a/components/sync_sessions/sync_sessions_metrics.cc
+++ b/components/sync_sessions/sync_sessions_metrics.cc
@@ -19,9 +19,9 @@ 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());
@@ -40,13 +40,13 @@ void SyncSessionsMetrics::RecordYoungestForeignTabAgeOnNTP(
 
 // 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;
     }