Adding the --load-component-extension flag.

chrome/browser/extensions/extension_file_browser_private_api.cc

Index: chrome/browser/extensions/extension_file_browser_private_api.cc
diff --git a/chrome/browser/extensions/extension_file_browser_private_api.cc b/chrome/browser/extensions/extension_file_browser_private_api.cc
index e23c4f7d703c405c0f8fa04e5de2ac76685b8eb4..226c73e707da92182e980dc4aaf13c8237607071 100644
--- a/chrome/browser/extensions/extension_file_browser_private_api.cc
+++ b/chrome/browser/extensions/extension_file_browser_private_api.cc
@@ -375,12 +375,7 @@ class RequestLocalFileSystemFunction::LocalFileSystemCallbackDispatcher
 
     // Make sure that only component extension can access the entire
     // local file system.
-    if (extension_->location() != Extension::COMPONENT
-#ifndef NDEBUG
-      && !CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kExposePrivateExtensionApi)
-#endif
-        ) {
+    if (extension_->location() != Extension::COMPONENT) {
       NOTREACHED() << "Private method access by non-component extension "
                    << extension_->id();
       return false;