arc: Register ARC content file system

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 19f94c6d392b27014d05468bd0366373e0207029..89c0a45b7fbf6d8e77bef571ba357217eefd1ad9 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -200,6 +200,7 @@
 #include "chrome/browser/chrome_browser_main_mac.h"
 #elif defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/arc/arc_auth_service.h"
+#include "chrome/browser/chromeos/arc/fileapi/arc_content_file_system_backend_delegate.h"
 #include "chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h"
 #include "chrome/browser/chromeos/attestation/platform_verification_impl.h"
 #include "chrome/browser/chromeos/chrome_browser_main_chromeos.h"
@@ -2754,7 +2755,7 @@ void ChromeContentBrowserClient::GetAdditionalFileSystemBackends(
       new drive::FileSystemBackendDelegate,
       new chromeos::file_system_provider::BackendDelegate,
       new chromeos::MTPFileSystemBackendDelegate(storage_partition_path),
-      external_mount_points,
+      new arc::ArcContentFileSystemBackendDelegate, external_mount_points,

[hidehiko, 2016/10/25 16:55:44]

I know you follow the existing code, but could you please add ()?

cf) the 2. of
https://sites.google.com/a/chromium.org/dev/developers/coding-style/cpp-dos-a...

[hashimoto, 2016/10/26 05:23:12]

Replaced with base::MakeUnique().

       storage::ExternalMountPoints::GetSystemInstance());
   backend->AddSystemMountPoints();
   DCHECK(backend->CanHandleType(storage::kFileSystemTypeExternal));