[LayoutNG] Disable scrollable overflow for NG-fieldsets.

The paint code doesn't like anonymous scrollable containers, so just
disable non-visible overflow support for LayoutNGFieldset.

Bug: 875235
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ice03f866bd3e61d8b0b8137089c4de254c0b81f5
Reviewed-on: https://chromium-review.googlesource.com/c/1264661Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597266}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1749,12 +1749,10 @@ crbug.com/591099 virtual/layout_ng_experimental/external/wpt/css/css-flexbox/ord
 
 # Fieldset in NG
 #
-crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-overflow-hidden.html [ Crash Pass ]
-crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-overflow.html [ Crash ]
+crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-overflow.html [ Failure ]
 crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-painting-order.html [ Failure ]
 crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-percentage-block-size.html [ Failure ]
-crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-percentage-padding.html [ Crash Pass ]
-crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-transform-translatez.html [ Crash Failure ]
+crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-transform-translatez.html [ Failure ]
 crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-vertical.html [ Failure ]
 crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/legend-align.html [ Failure ]
 crbug.com/875235 virtual/layout_ng_experimental/external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/legend-auto-margins.html [ Failure ]

third_party/blink/renderer/core/layout/ng/layout_ng_fieldset.cc

@@ -32,8 +32,8 @@ void LayoutNGFieldset::AddChild(LayoutObject* new_child,
     scoped_refptr<ComputedStyle> new_style =
         ComputedStyle::CreateAnonymousStyleWithDisplay(StyleRef(),
                                                        EDisplay::kFlowRoot);
-    new_style->SetOverflowX(StyleRef().OverflowX());
-    new_style->SetOverflowY(StyleRef().OverflowY());
+    // TODO(crbug.com/875235): When the paint code is ready for anonymous
+    // scrollable containers, inherit overflow-x and overflow-y here.
 
     new_style->SetPaddingTop(StyleRef().PaddingTop());
     new_style->SetPaddingRight(StyleRef().PaddingRight());