[Sync] Fix EnableDisableSingleClientTest

chrome/browser/sync/test/integration/sync_test.h

Index: chrome/browser/sync/test/integration/sync_test.h
diff --git a/chrome/browser/sync/test/integration/sync_test.h b/chrome/browser/sync/test/integration/sync_test.h
index da2ac60d9a4f83090ea9a3676fd5c96ab6be5e32..0bcfa2d8d704bad620dd0588d15548cccd4e7cd4 100644
--- a/chrome/browser/sync/test/integration/sync_test.h
+++ b/chrome/browser/sync/test/integration/sync_test.h
@@ -43,6 +43,10 @@ class ProfileSyncServiceHarness;
 class P2PInvalidationForwarder;
 class P2PSyncRefresher;
 
+namespace arc {
+class SyncArcPackageHelper;
+}  // namespace arc
+
 namespace base {
 class CommandLine;
 class ScopedTempDir;
@@ -252,6 +256,8 @@ class SyncTest : public InProcessBrowserTest {
   // Triggers a sync for the given |model_types| for the Profile at |index|.
   void TriggerSyncForModelTypes(int index, syncer::ModelTypeSet model_types);
 
+  arc::SyncArcPackageHelper* sync_arc_helper();
+
  protected:
   // Add custom switches needed for running the test.
   virtual void AddTestSwitches(base::CommandLine* cl);