Fix install verification for sideloaded extensions without update urls

chrome/browser/extensions/install_signer.h

Index: chrome/browser/extensions/install_signer.h
diff --git a/chrome/browser/extensions/install_signer.h b/chrome/browser/extensions/install_signer.h
index a6177c4f5cacbee127c2c5b76956c4829dbf0191..56f23b4f1455e9ffb2905ce6f82ac8335b63e586 100644
--- a/chrome/browser/extensions/install_signer.h
+++ b/chrome/browser/extensions/install_signer.h
@@ -38,9 +38,14 @@ struct InstallSignature {
   // The date that the signature should expire, in YYYY-MM-DD format.
   std::string expire_date;
 
-  // The time this signature was obtained from the server.
+  // The time this signature was obtained from the server. Note that this
+  // is computed locally and *not* signed by the server key.
   base::Time timestamp;
 
+  // The set of ids that the server indicated were invalid (ie not signed).
+  // Note that this is computed locally and *not* signed by the signature.
+  ExtensionIdSet invalid_ids;
+
   InstallSignature();
   ~InstallSignature();