Fix incorrectly calculated content_size for fragments that create new FC

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.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/ng/ng_box.h"
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_physical_fragment.h"
 #include "core/layout/ng/ng_length_utils.h"
@@ skipping 116 matching lines @@
 
 // Verifies the collapsing margins case for the next pair:
 // - top margin of a box and top margin of its first in-flow child.
 //
 // Test case's HTML representation:
 // <div style="margin-top: 20px; height: 50px;">  <!-- DIV1 -->
 //    <div style="margin-top: 10px"></div>        <!-- DIV2 -->
 // </div>
 //
 // Expected:
+// - Empty margin strut of the fragment that establishes new formatting context
 // - Margins are collapsed resulting a single margin 20px = max(20px, 10px)
 // - The top offset of DIV2 == 20px
 TEST_F(NGBlockLayoutAlgorithmTest, CollapsingMarginsCase1) {
   const int kHeight = 50;
   const int kDiv1MarginTop = 20;
   const int kDiv2MarginTop = 10;
 
   // DIV1
   RefPtr<ComputedStyle> div1_style = ComputedStyle::create();
   div1_style->setHeight(Length(kHeight, Fixed));
   div1_style->setMarginTop(Length(kDiv1MarginTop, Fixed));
   NGBox* div1 = new NGBox(div1_style.get());
 
   // DIV2
   RefPtr<ComputedStyle> div2_style = ComputedStyle::create();
   div2_style->setMarginTop(Length(kDiv2MarginTop, Fixed));
   NGBox* div2 = new NGBox(div2_style.get());
 
   div1->SetFirstChild(div2);
 
   auto* space =
       new NGConstraintSpace(HorizontalTopBottom, LeftToRight,
                             NGLogicalSize(LayoutUnit(100), NGSizeIndefinite));
   space->SetIsNewFormattingContext(true);
   NGPhysicalFragment* frag = RunBlockLayoutAlgorithm(space, div1);
 
-  EXPECT_EQ(NGMarginStrut({LayoutUnit(kDiv1MarginTop)}), frag->MarginStrut());
+  EXPECT_TRUE(frag->MarginStrut().IsEmpty());
   ASSERT_EQ(frag->Children().size(), 1UL);
   const NGPhysicalFragmentBase* div2_fragment = frag->Children()[0];
   EXPECT_EQ(NGMarginStrut({LayoutUnit(kDiv2MarginTop)}),
             div2_fragment->MarginStrut());
   EXPECT_EQ(kDiv1MarginTop, div2_fragment->TopOffset());
 }
 
 // Verifies the collapsing margins case for the next pair:
 // - bottom margin of box and top margin of its next in-flow following sibling.
 //
@@ skipping 308 matching lines @@
 
   EXPECT_EQ(frag->Width(), LayoutUnit(kWidth + kPaddingLeft));
   EXPECT_EQ(frag->Type(), NGPhysicalFragmentBase::FragmentBox);
   ASSERT_EQ(frag->Children().size(), 1UL);
 
   const NGPhysicalFragmentBase* child = frag->Children()[0];
   EXPECT_EQ(child->Width(), LayoutUnit(12));
 }
 }  // namespace
 }  // namespace blink