Add a "key" entry to InstallWarnings, remove InstallWarning::Format

chrome/browser/extensions/api/developer_private/developer_private_api.cc

Index: chrome/browser/extensions/api/developer_private/developer_private_api.cc
diff --git a/chrome/browser/extensions/api/developer_private/developer_private_api.cc b/chrome/browser/extensions/api/developer_private/developer_private_api.cc
index 682de9a53c971e54cfb2f237d8df028654fffae5..1b0d319023c18897db2a3c8dface4648746c976e 100644
--- a/chrome/browser/extensions/api/developer_private/developer_private_api.cc
+++ b/chrome/browser/extensions/api/developer_private/developer_private_api.cc
@@ -304,7 +304,6 @@ scoped_ptr<developer::ItemInfo>
              item.install_warnings().begin();
          it != item.install_warnings().end(); ++it) {
       developer::InstallWarning* warning = new developer::InstallWarning();
-      warning->is_html = (it->format == InstallWarning::FORMAT_HTML);
       warning->message = it->message;
       info->install_warnings.push_back(make_linked_ptr(warning));
     }