[layoutng] Better handling of border and padding

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc

 // Copyright 2016 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.
 
 #include "core/layout/ng/ng_block_layout_algorithm.h"
 
 #include "core/layout/LayoutBox.h"
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_fragment_builder.h"
 #include "core/layout/ng/ng_fragment.h"
@@ skipping 20 matching lines @@
     PassRefPtr<const ComputedStyle> style,
     NGBox* first_child)
     : style_(style), first_child_(first_child), state_(kStateInit) {
   DCHECK(style_);
 }
 
 bool NGBlockLayoutAlgorithm::Layout(const NGConstraintSpace* constraint_space,
                                     NGPhysicalFragment** out) {
   switch (state_) {
     case kStateInit: {
+      border_and_padding_ =
+          computeBorders(*style_) + computePadding(*constraint_space, *style_);
+
       LayoutUnit inline_size =
           computeInlineSizeForFragment(*constraint_space, *style_);
       // TODO(layout-ng): For quirks mode, should we pass blockSize instead of
       // -1?
       LayoutUnit block_size = computeBlockSizeForFragment(
           *constraint_space, *style_, LayoutUnit(-1));
-      constraint_space_for_children_ =
-          new NGConstraintSpace(*constraint_space, NGLogicalOffset(),
-                                NGLogicalSize(inline_size, block_size));
-      content_size_ = LayoutUnit();
+      constraint_space_for_children_ = new NGConstraintSpace(
+          *constraint_space, NGLogicalOffset(),
+          NGLogicalSize(inline_size - border_and_padding_.inline_start,

[mstensho (USE GERRIT), 2016/09/12 20:05:50]

I may lack some understanding of how this thing works, but here goes: Why
subtract only one side? What about inline end and block end?

[cbiesinger, 2016/09/13 18:04:54]

Great point! That should be changed, thanks.

+                        block_size - border_and_padding_.block_start));
+      content_size_ = border_and_padding_.block_start;
 
       builder_ = new NGFragmentBuilder(NGPhysicalFragmentBase::FragmentBox);
       builder_->SetInlineSize(inline_size).SetBlockSize(block_size);
       current_child_ = first_child_;
       state_ = kStateChildLayout;
       return false;
     }
     case kStateChildLayout: {
       if (current_child_) {
         NGFragment* fragment;
         if (!current_child_->Layout(constraint_space_for_children_, &fragment))
           return false;
         NGBoxStrut child_margins = computeMargins(
             *constraint_space_for_children_, *current_child_->Style());
 
         LayoutUnit margin_block_start =
             CollapseMargins(child_margins, fragment->MarginStrut());
 
         // TODO(layout-ng): Support auto margins
         builder_->AddChild(fragment,
-                           NGLogicalOffset(child_margins.inline_start,
+                           NGLogicalOffset(border_and_padding_.inline_start +
+                                               child_margins.inline_start,
                                            content_size_ + margin_block_start));
 
         content_size_ += fragment->BlockSize() + margin_block_start;
         max_inline_size_ =
-            std::max(max_inline_size_,
-                     fragment->InlineSize() + child_margins.InlineSum());
+            std::max(max_inline_size_, fragment->InlineSize() +
+                                           child_margins.InlineSum() +
+                                           border_and_padding_.InlineSum());
         current_child_ = current_child_->NextSibling();
         if (current_child_)
           return false;
       }
       state_ = kStateFinalize;
       return false;
     }
     case kStateFinalize: {
+      content_size_ += border_and_padding_.block_end;
       // Recompute the block-axis size now that we know our content size.
       LayoutUnit block_size = computeBlockSizeForFragment(
           *constraint_space, *style_, content_size_);
 
       builder_->SetBlockSize(block_size)
           .SetInlineOverflow(max_inline_size_)
           .SetBlockOverflow(content_size_);
       *out = builder_->ToFragment();
       state_ = kStateInit;
       return true;
@@ skipping 25 matching lines @@
     margin_block_start = ComputeCollapsedMarginBlockStart(
         prev_child_margin_strut_, curr_margin_strut);
 
   prev_child_margin_strut_ = curr_margin_strut;
   // TODO(layout-ng): support other Margin Collapsing use cases,
   // i.e. support 0 height elements etc.
   return margin_block_start;
 }
 
 }  // namespace blink