Enable LayoutNG for input[type=image]

It has no reasons to use the legacy layout.

Bug: 1040826
Change-Id: I2adf8160551d5ec5fa77d506b1e8d930bff43416
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2299659
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Auto-Submit: Kent Tamura <tkent@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788551}

third_party/blink/renderer/core/html/forms/image_input_type.cc

@@ -105,10 +105,6 @@ void ImageInputType::HandleDOMActivateEvent(Event& event) {
   event.SetDefaultHandled();
 }
 
-bool ImageInputType::TypeShouldForceLegacyLayout() const {
-  return true;
-}
-
 LayoutObject* ImageInputType::CreateLayoutObject(const ComputedStyle& style,
                                                  LegacyLayout legacy) const {
   if (use_fallback_content_) {

third_party/blink/renderer/core/html/forms/image_input_type.h

@@ -50,7 +50,6 @@ class ImageInputType final : public BaseButtonInputType {
   void AppendToFormData(FormData&) const override;
   String ResultForDialogSubmit() const override;
   bool SupportsValidation() const override;
-  bool TypeShouldForceLegacyLayout() const override;
   LayoutObject* CreateLayoutObject(const ComputedStyle&,
                                    LegacyLayout) const override;
   void HandleDOMActivateEvent(Event&) override;