Issue #2313397 by tim.plunkett: Replace FormBuilderInterface::setValue() with FormStateInterface::setValueForElement().

Issue #2308821 by tim.plunkett: Replace FormErrorInterface with $form_state->setErrorByName() and $form_state->setError().

Issue #2299421 by amitgoyal, joshi.rohit100: Remove all usage of drupal_build_form() as deprecated and replaced by FormBuilderInterface::buildForm().

Issue #2257835 by tim.plunkett, sun, Jalandhar: Move form submission logic out of FormBuilder into a new class.

Issue #2174443 by mr.baileys, David_Rothstein: Add security hardening protection option for programmatic form submissions to Drupal 8 (and backport to Drupal 6?).

Issue #2121175 by Codenator, tim.plunkett, cosmicdreams, jayeshanandani, grom358, ianthomas_uk, Xano: Remove usage of drupal_get_form().

Issue #1978924 by tim.plunkett, ParisLiakos, disasm, Luxian, vijaycs85, YesCT, vaibhavjain, Pancho: Convert locale_translate_export_form to a Controller.

Issue #2072995 by claudiu.cristea, yched: Change notice: Move FAPI callbacks for file/image widgets in classes.

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, alexpott, larowlan, Damien Tournoud: Replace almost all remaining superglobals (, , etc.) with Symfony Request object.

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, larowlan, Damien Tournoud: Replace all remaining superglobals (, , etc.) with Symfony Request object.