[Sync] Fix namespaces for the browser_sync component.

chrome/browser/sync/sessions/sync_sessions_metrics_android.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 "chrome/browser/sync/sessions/sync_sessions_metrics_android.h"
 
 #include <string>
 
 #include "base/metrics/field_trial.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 17 matching lines @@
   // conserve battery. This means that the foreign tab data may be quite stale.
   // This would drastically distort the metric we want to emit here, however the
   // revisit experiement disables said optimization, allowing us to collect
   // valid data but at the cost of a much smaller sample size.
   const std::string group_name =
       base::FieldTrialList::FindFullName("PageRevisitInstrumentation");
   bool shouldInstrument = group_name == "Enabled";
   if (shouldInstrument) {
     Profile* profile = ProfileManager::GetActiveUserProfile();
     if (profile) {
-      ProfileSyncService* sync =
+      browser_sync::ProfileSyncService* sync =
           ProfileSyncServiceFactory::GetForProfile(profile);
       if (sync) {
         sync_sessions::SessionsSyncManager* sessions =
             static_cast<sync_sessions::SessionsSyncManager*>(
                 sync->GetSessionsSyncableService());
         if (sessions) {
           sync_sessions::SyncSessionsMetrics::RecordYoungestForeignTabAgeOnNTP(
               sessions);
         }
       }
     }
   }
 }