Mount MTP devices in Chrome OS Files.app.

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 18dd4c317acea99346143bccf39206e1b75a18cc..130fe12b75bd40d715c20b896249fc34204d12e1 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -167,6 +167,7 @@
 #include "chrome/browser/chromeos/drive/fileapi/file_system_backend_delegate.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/backend_delegate.h"
 #include "chrome/browser/chromeos/fileapi/file_system_backend.h"
+#include "chrome/browser/chromeos/fileapi/mtp_file_system_backend_delegate.h"
 #include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/system/input_device_settings.h"
@@ -2510,6 +2511,7 @@ void ChromeContentBrowserClient::GetAdditionalFileSystemBackends(
   chromeos::FileSystemBackend* backend = new chromeos::FileSystemBackend(
       new drive::FileSystemBackendDelegate,
       new chromeos::file_system_provider::BackendDelegate,
+      new chromeos::MTPFileSystemBackendDelegate(storage_partition_path),
       browser_context->GetSpecialStoragePolicy(),
       external_mount_points,
       fileapi::ExternalMountPoints::GetSystemInstance());