Reland "Fix form resubmissions happening silently."

This reverts commit 9f3fcfea463d525af6b525318998edb72c09a7e1.

BUG=263508

Review URL: https://chromiumcodereview.appspot.com/22982011

git-svn-id: svn://svn.chromium.org/blink/trunk@157253 bbb929c8-8fbe-4397-9dbb-9b2b20218538