Make full-form autofill the only implementation on iOS.

ios/chrome/browser/autofill/form_suggestion_controller.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/autofill/form_suggestion_controller.h"
 
 #include <memory>
 
 #include "base/ios/ios_util.h"
 #include "base/ios/weak_nsobject.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_block.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
-#include "components/autofill/core/browser/autofill_field_trial_ios.h"
 #include "components/autofill/core/browser/autofill_popup_delegate.h"
 #import "components/autofill/ios/browser/form_suggestion.h"
 #import "ios/chrome/browser/autofill/form_input_accessory_view_controller.h"
 #import "ios/chrome/browser/autofill/form_suggestion_provider.h"
 #import "ios/chrome/browser/autofill/form_suggestion_view.h"
 #import "ios/chrome/browser/passwords/password_generation_utils.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/web/public/url_scheme_util.h"
 #import "ios/web/public/web_state/crw_web_view_proxy.h"
 #import "ios/web/public/web_state/js/crw_js_injection_receiver.h"
@@ skipping 270 matching lines @@
     return;
 
   // Send the suggestion to the provider. Upon completion advance the cursor
   // for single-field Autofill, or close the keyboard for full-form Autofill.
   base::WeakNSObject<FormSuggestionController> weakSelf(self);
   [_provider
       didSelectSuggestion:suggestion
                  forField:base::SysUTF8ToNSString(_suggestionState->field_name)
                      form:base::SysUTF8ToNSString(_suggestionState->form_name)
         completionHandler:^{
-          if (autofill::AutofillFieldTrialIOS::IsFullFormAutofillEnabled()) {
-            [[weakSelf accessoryViewDelegate] closeKeyboardWithoutButtonPress];
-          } else {
-            [[weakSelf accessoryViewDelegate]
-                selectNextElementWithoutButtonPress];
-          }
+          [[weakSelf accessoryViewDelegate] closeKeyboardWithoutButtonPress];
         }];
   _provider = nil;
 }
 
 - (id<FormInputAccessoryViewProvider>)accessoryViewProvider {
   return self;
 }
 
 #pragma mark FormInputAccessoryViewProvider
 
@@ skipping 41 matching lines @@
 
 - (void)resizeAccessoryView {
   [self updateKeyboard:_suggestionState.get()];
 }
 
 - (BOOL)getLogKeyboardAccessoryMetrics {
   return YES;
 }
 
 @end