FileManageBrowserTestBase: disable NaCl loading component extensions

These extensions are not used by the Files.app browser tests and cause
ASAN flakes due to an unrelated NaCl bug 788671.

Skirt around that bug here by not loading these NaCl-using extensions.
Side-effect: these browser tests hopefully run a little faster.

Bug: 788671,836254
Change-Id: Ie528cad328d76f2ff0ee97c994f2bc539de86a98
Reviewed-on: https://chromium-review.googlesource.com/1055351
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557831}

chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc

@@ -567,6 +567,10 @@ void FileManagerBrowserTestBase::SetUpCommandLine(
     command_line->AppendSwitch(switches::kIncognito);
   }
 
+  // Block NaCl loading Files.app components crbug.com/788671
+  command_line->AppendSwitch(chromeos::switches::kDisableZipArchiverUnpacker);
+  command_line->AppendSwitch(chromeos::switches::kDisableZipArchiverPacker);
+
   ExtensionApiTest::SetUpCommandLine(command_line);
 }