[layoutng] Remove an unnecessary duplicate call to ComputePadding

Also, makes CalculateBorderScrollbarPadding equivalent to
ComputeBorder + ComputePadding + GetScrollbarSizes.

This also makes the padding set on the fragment more correct.

R=eae@chromium.org

Bug: 635619
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I8db38ca5955d30fa789a636e5c6deb2ec1fd1829
Reviewed-on: https://chromium-review.googlesource.com/1169321
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582272}

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

@@ -347,8 +347,12 @@ NGLogicalOffset NGBlockLayoutAlgorithm::CalculateLogicalOffset(
 }
 
 scoped_refptr<NGLayoutResult> NGBlockLayoutAlgorithm::Layout() {
+  NGBoxStrut borders = ComputeBorders(ConstraintSpace(), Node());
+  NGBoxStrut padding = ComputePadding(ConstraintSpace(), Node());
   border_scrollbar_padding_ =
-      CalculateBorderScrollbarPadding(ConstraintSpace(), Node());
+      ConstraintSpace().IsAnonymous()
+          ? NGBoxStrut()
+          : borders + padding + Node().GetScrollbarSizes();
 
   NGLogicalSize border_box_size = CalculateBorderBoxSize(
       ConstraintSpace(), Node(), CalculateDefaultBlockSize());
@@ -630,7 +634,7 @@ scoped_refptr<NGLayoutResult> NGBlockLayoutAlgorithm::Layout() {
 
   container_builder_.SetEndMarginStrut(end_margin_strut);
   container_builder_.SetIntrinsicBlockSize(intrinsic_block_size_);
-  container_builder_.SetPadding(ComputePadding(ConstraintSpace(), Style()));
+  container_builder_.SetPadding(padding);
 
   // We only finalize for fragmentation if the fragment has a BFC block offset.
   // This may occur with a zero block size fragment. We need to know the BFC

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

@@ -684,6 +684,22 @@ NGBoxStrut ComputeBorders(const NGConstraintSpace& constraint_space,
   return borders;
 }
 
+NGBoxStrut ComputeBorders(const NGConstraintSpace& constraint_space,
+                          const NGLayoutInputNode node) {
+  // If we are producing an anonymous fragment (e.g. a column), it has no
+  // borders, padding or scrollbars. Using the ones from the container can only
+  // cause trouble.
+  if (constraint_space.IsAnonymous())
+    return NGBoxStrut();
+
+  if (node.GetLayoutBox()->IsTableCell()) {
+    LayoutBox* box = node.GetLayoutBox();
+    return NGBoxStrut(box->BorderStart(), box->BorderEnd(), box->BorderBefore(),
+                      box->BorderAfter());
+  }
+  return ComputeBorders(constraint_space, node.Style());
+}
+
 NGBoxStrut ComputePadding(const NGConstraintSpace& constraint_space,
                           const ComputedStyle& style) {
   // If we are producing an anonymous fragment (e.g. a column) we shouldn't
@@ -703,6 +719,27 @@ NGBoxStrut ComputePadding(const NGConstraintSpace& constraint_space,
   return padding;
 }
 
+NGBoxStrut ComputePadding(const NGConstraintSpace& constraint_space,
+                          const NGLayoutInputNode node) {
+  // If we are producing an anonymous fragment (e.g. a column), it has no
+  // borders, padding or scrollbars. Using the ones from the container can only
+  // cause trouble.
+  if (constraint_space.IsAnonymous())
+    return NGBoxStrut();
+
+  NGBoxStrut padding = ComputePadding(constraint_space, node.Style());
+  if (node.GetLayoutBox()->IsTableCell()) {
+    // Use values calculated by the table layout code
+    const LayoutTableCell* cell = ToLayoutTableCell(node.GetLayoutBox());
+    // TODO(karlo): intrinsic padding can sometimes be negative; that
+    // seems insane, but works in the old code; in NG it trips
+    // DCHECKs.
+    padding.block_start += LayoutUnit(cell->IntrinsicPaddingBefore());
+    padding.block_end += LayoutUnit(cell->IntrinsicPaddingAfter());
+  }
+  return padding;
+}
+
 void ResolveInlineMargins(const ComputedStyle& style,
                           const ComputedStyle& containing_block_style,
                           LayoutUnit available_inline_size,
@@ -813,29 +850,13 @@ LayoutUnit ConstrainByMinMax(LayoutUnit length,
 NGBoxStrut CalculateBorderScrollbarPadding(
     const NGConstraintSpace& constraint_space,
     const NGBlockNode node) {
-  const ComputedStyle& style = node.Style();
-
   // If we are producing an anonymous fragment (e.g. a column), it has no
   // borders, padding or scrollbars. Using the ones from the container can only
   // cause trouble.
   if (constraint_space.IsAnonymous())
     return NGBoxStrut();
-  NGBoxStrut border_intrinsic_padding;
-  if (node.GetLayoutBox()->IsTableCell()) {
-    // Use values calculated by the table layout code
-    const LayoutTableCell* cell = ToLayoutTableCell(node.GetLayoutBox());
-    // TODO(karlo): intrinsic padding can sometimes be negative; that
-    // seems insane, but works in the old code; in NG it trips
-    // DCHECKs.
-    border_intrinsic_padding = NGBoxStrut(
-        cell->BorderStart(), cell->BorderEnd(),
-        cell->BorderBefore() + LayoutUnit(cell->IntrinsicPaddingBefore()),
-        cell->BorderAfter() + LayoutUnit(cell->IntrinsicPaddingAfter()));
-  } else {
-    border_intrinsic_padding = ComputeBorders(constraint_space, style);
-  }
-  return border_intrinsic_padding + ComputePadding(constraint_space, style) +
-         node.GetScrollbarSizes();
+  return ComputeBorders(constraint_space, node) +
+         ComputePadding(constraint_space, node) + node.GetScrollbarSizes();
 }
 
 NGLogicalSize CalculateBorderBoxSize(const NGConstraintSpace& constraint_space,

third_party/blink/renderer/core/layout/ng/ng_length_utils.h

@@ -168,12 +168,18 @@ CORE_EXPORT NGBoxStrut ComputeMarginsForSelf(const NGConstraintSpace&,
 CORE_EXPORT NGBoxStrut ComputeMinMaxMargins(const ComputedStyle& parent_style,
                                             NGLayoutInputNode child);
 
-CORE_EXPORT NGBoxStrut ComputeBorders(const NGConstraintSpace& constraint_space,
+CORE_EXPORT NGBoxStrut ComputeBorders(const NGConstraintSpace&,
                                       const ComputedStyle&);
 
+CORE_EXPORT NGBoxStrut ComputeBorders(const NGConstraintSpace&,
+                                      const NGLayoutInputNode);
+
 CORE_EXPORT NGBoxStrut ComputePadding(const NGConstraintSpace&,
                                       const ComputedStyle&);
 
+CORE_EXPORT NGBoxStrut ComputePadding(const NGConstraintSpace&,
+                                      const NGLayoutInputNode);
+
 // Convert inline margins from computed to used values. This will resolve 'auto'
 // values and over-constrainedness. This uses the available size from the
 // constraint space and inline size to compute the margins that are auto, if