Disallow packing or loading unpacked manifest v1 extensions.

chrome/browser/extensions/startup_helper.cc

Index: chrome/browser/extensions/startup_helper.cc
diff --git a/chrome/browser/extensions/startup_helper.cc b/chrome/browser/extensions/startup_helper.cc
index b0c90bcc804918565bd00f1f4ccda4aebb86ee64..7535e3c0b698d4008cc409b9c87ef7a8e067c651 100644
--- a/chrome/browser/extensions/startup_helper.cc
+++ b/chrome/browser/extensions/startup_helper.cc
@@ -51,8 +51,10 @@ bool StartupHelper::PackExtension(const CommandLine& cmd_line) {
 
   // Launch a job to perform the packing on the file thread.  Ignore warnings
   // from the packing process. (e.g. Overwrite any existing crx file.)
-  pack_job_ = new PackExtensionJob(this, src_dir, private_key_path,
-                                   ExtensionCreator::kOverwriteCRX);
+  int run_flags =
+      ExtensionCreator::kOverwriteCRX |
+      ExtensionCreator::kRequireModernManifestVersion;
+  pack_job_ = new PackExtensionJob(this, src_dir, private_key_path, run_flags);
   pack_job_->set_asynchronous(false);
   pack_job_->Start();