Fix Arc integration test.

chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc

Index: chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc
diff --git a/chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc b/chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc
index ef5a1c8b50b6ad02513e6327358e45955d0f7d3e..e094e0f434865dc49b1c488fb42e5e969f0d2f41 100644
--- a/chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc
+++ b/chrome/browser/sync/test/integration/two_client_arc_package_sync_test.cc
@@ -6,6 +6,7 @@
 #include "chrome/browser/sync/test/integration/sync_arc_package_helper.h"
 #include "chrome/browser/sync/test/integration/sync_integration_test_util.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
+#include "chrome/browser/ui/app_list/arc/arc_app_list_prefs_factory.h"
 
 namespace arc {
 
@@ -37,6 +38,10 @@ class TwoClientArcPackageSyncTest : public SyncTest {
     return sync_helper_ != nullptr;
   }
 
+  void SetUpOnMainThread() override {

[lgcheng, 2017/02/22 23:36:44]

Moved from sync_arc_package_helper. It seems the execution order of
SetFactoryForSyncTest() and setupService() is not guaranteed by compiler due to
the complexity of construction of ArcAppListPrefs. 

+    ArcAppListPrefsFactory::SetFactoryForSyncTest();
+  }
+
   void TearDownOnMainThread() override {
     sync_helper_->CleanUp();
     sync_helper_ = nullptr;