Enforce using a publisher proof for CRX3 (#12551)

* Enforce using a publisher proof for CRX3
* add a new line

chromium_src/components/component_updater/component_updater_service.cc

@@ -3,7 +3,25 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * you can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "components/crx_file/crx_verifier.h"
-#define CRX3_WITH_PUBLISHER_PROOF CRX3
+#include "base/feature_list.h"
+#include "components/update_client/update_client.h"
+
+namespace {
+const base::Feature kEnforceCRX3PublisherProof{
+    "EnforceCRX3PublisherProof", base::FEATURE_ENABLED_BY_DEFAULT};
+
+crx_file::VerifierFormat GetVerifierFormat() {
+  if (base::FeatureList::IsEnabled(kEnforceCRX3PublisherProof))
+    return crx_file::VerifierFormat::CRX3_WITH_PUBLISHER_PROOF;
+
+  return crx_file::VerifierFormat::CRX3;
+}
+}  // namespace
+
+#define crx_format_requirement                  \
+  crx_format_requirement = GetVerifierFormat(); \
+  crx_file::VerifierFormat _temp_var;           \
+  ALLOW_UNUSED_LOCAL(_temp_var);                \
+  _temp_var
 #include "src/components/component_updater/component_updater_service.cc"
-#undef CRX3_WITH_PUBLISHER_PROOF
+#undef crx_format_requirement