arc: Register ARC content file system

chrome/browser/platform_util_unittest.cc

Index: chrome/browser/platform_util_unittest.cc
diff --git a/chrome/browser/platform_util_unittest.cc b/chrome/browser/platform_util_unittest.cc
index 12480a7dbca5f318f32c189d4a58ebcac3a491d2..c7786ddb4a0777257a632891b67dbcc7a23c3500 100644
--- a/chrome/browser/platform_util_unittest.cc
+++ b/chrome/browser/platform_util_unittest.cc
@@ -55,7 +55,7 @@ class PlatformUtilTestContentBrowserClient : public ChromeContentBrowserClient {
 
     // New FileSystemBackend that uses our MockSpecialStoragePolicy.
     chromeos::FileSystemBackend* backend = new chromeos::FileSystemBackend(
-        nullptr, nullptr, nullptr, external_mount_points,
+        nullptr, nullptr, nullptr, nullptr, external_mount_points,
         storage::ExternalMountPoints::GetSystemInstance());
     additional_backends->push_back(backend);
   }