[FlexNG] Set correct main axis offset for row-reverse flex containers

We had been doing row, column, and column-reverse correctly, but not
row-reverse. So the items in row-reverse containers with asymmetric
inline padding/border were positioned incorrectly.

Bug: 845235
Change-Id: Icbfd2bae96070cd14590d4ffe6224278cc3da353
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1907197Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714106}

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

@@ -515,6 +515,8 @@ scoped_refptr<const NGLayoutResult> NGFlexLayoutAlgorithm::Layout() {
                            ? LayoutUnit()
                            : border_scrollbar_padding_.block_start;
     cross_axis_offset = border_scrollbar_padding_.inline_start;
+  } else if (Style().ResolvedIsRowReverseFlexDirection()) {
+    main_axis_offset = border_scrollbar_padding_.inline_end;
   }
   FlexLine* line;
   while (

third_party/blink/web_tests/TestExpectations

@@ -1387,9 +1387,7 @@ crbug.com/591099 external/wpt/css/css-flexbox/flexbox_align-items-stretch-3.html
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/auto-height-column-with-border-and-padding.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-align-vertical-writing-mode.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-align.html [ Failure ]
-crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-flow-border.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-flow-margins-auto-size.html [ Failure ]
-crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-flow-padding.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flex-order.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flexbox-baseline-margins.html [ Failure ]
 crbug.com/591099 virtual/layout_ng_flex_box/css3/flexbox/flexbox-baseline.html [ Failure ]