[LayoutNG] A different approach to multi-col.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc
index 4e2bf337d2204074f826676ea8677d6e1e853d5a..9ca6be40dee5d66a6a996a565203d08476667dd9 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc
@@ -26,16 +26,25 @@ namespace {
 using testing::ElementsAre;
 using testing::Pointee;
 
-NGConstraintSpace* ConstructConstraintSpace(NGWritingMode writing_mode,
-                                            TextDirection direction,
-                                            NGLogicalSize size,
-                                            bool shrink_to_fit = false) {
+NGConstraintSpace* ConstructConstraintSpace(
+    NGWritingMode writing_mode,
+    TextDirection direction,
+    NGLogicalSize size,
+    bool shrink_to_fit = false,
+    LayoutUnit fragmentainer_space_available = LayoutUnit()) {
+  NGFragmentationType block_fragmentation =
+      fragmentainer_space_available != LayoutUnit()
+          ? NGFragmentationType::kFragmentColumn
+          : NGFragmentationType::kFragmentNone;
+
   return NGConstraintSpaceBuilder(writing_mode)
       .SetAvailableSize(size)
       .SetPercentageResolutionSize(size)
       .SetTextDirection(direction)
       .SetWritingMode(writing_mode)
       .SetIsShrinkToFit(shrink_to_fit)
+      .SetFragmentainerSpaceAvailable(fragmentainer_space_available)
+      .SetFragmentationType(block_fragmentation)
       .ToConstraintSpace();
 }
 
@@ -60,14 +69,13 @@ class NGBlockLayoutAlgorithmTest
 
   RefPtr<NGPhysicalBoxFragment> RunBlockLayoutAlgorithm(
       NGConstraintSpace* space,
-      NGBlockNode* first_child) {
-    NGBlockNode parent(style_.get());
-    parent.SetFirstChild(first_child);
+      NGBlockNode* first_child,
+      NGBreakToken* break_token = nullptr) {
+    NGBlockNode* parent = new NGBlockNode(style_.get());
+    parent->SetFirstChild(first_child);
 
     RefPtr<NGPhysicalFragment> fragment =
-        NGBlockLayoutAlgorithm(/* layout_object */ nullptr, style_.get(),
-                               first_child, space)
-            .Layout();
+        NGBlockLayoutAlgorithm(parent, space).Layout();
 
     return toNGPhysicalBoxFragment(fragment.get());
   }
@@ -86,11 +94,13 @@ class NGBlockLayoutAlgorithmTest
   MinAndMaxContentSizes RunComputeMinAndMax(NGBlockNode* first_child) {
     // The constraint space is not used for min/max computation, but we need
     // it to create the algorithm.
+    NGBlockNode* node = new NGBlockNode(style_.get());
+    node->SetFirstChild(first_child);
+
     NGConstraintSpace* space =
         ConstructConstraintSpace(kHorizontalTopBottom, TextDirection::kLtr,
                                  NGLogicalSize(LayoutUnit(), LayoutUnit()));
-    NGBlockLayoutAlgorithm algorithm(/* layout_object */ nullptr, style_.get(),
-                                     first_child, space);
+    NGBlockLayoutAlgorithm algorithm(node, space);
     EXPECT_TRUE(algorithm.ComputeMinAndMaxContentSizes().has_value());
     return *algorithm.ComputeMinAndMaxContentSizes();
   }
@@ -1293,7 +1303,7 @@ class FragmentChildIterator {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyMulticol) {
+/*TEST_F(NGBlockLayoutAlgorithmTest, EmptyMulticol) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(2);
@@ -1317,7 +1327,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyMulticol) {
 
   // There should be nothing inside the multicol container.
   EXPECT_FALSE(FragmentChildIterator(fragment).NextChild());
-}
+}*/
 
 // Test case's HTML representation:
 //  <div id="parent" style="columns:2; column-fill:auto; column-gap:10px;
@@ -1326,7 +1336,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyMulticol) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyBlock) {
+/*TEST_F(NGBlockLayoutAlgorithmTest, EmptyBlock) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(2);
@@ -1364,8 +1374,306 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyBlock) {
   EXPECT_EQ(LayoutUnit(), fragment->Height());
   EXPECT_EQ(0UL, fragment->Children().size());
   EXPECT_FALSE(iterator.NextChild());
+}*/
+
+// Tests that a block child won't fragment if it doesn't reach the fragmentation
+// line.
+TEST_F(NGBlockLayoutAlgorithmTest, NoFragmentation) {
+  setBodyInnerHTML(R"HTML(
+      <!DOCTYPE html>
+      <style>
+        #container {
+          width: 150px;
+          height: 200px;
+        }
+      </style>
+      <div id='container'></div>
+  )HTML");
+
+  LayoutUnit kFragmentainerSpaceAvailable(200);
+
+  NGBlockNode* node = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  auto* space = ConstructConstraintSpace(
+      kHorizontalTopBottom, TextDirection::kLtr,
+      NGLogicalSize(LayoutUnit(1000), NGSizeIndefinite), false,
+      kFragmentainerSpaceAvailable);
+
+  // We should only have one 150x200 fragment with no fragmentation.
+  RefPtr<const NGPhysicalFragment> fragment =
+      NGBlockLayoutAlgorithm(node, space).Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_TRUE(fragment->BreakToken()->IsFinished());
+}
+
+TEST_F(NGBlockLayoutAlgorithmTest, SimpleFragmentation) {
+  setBodyInnerHTML(R"HTML(
+      <!DOCTYPE html>
+      <style>
+        #container {
+          width: 150px;
+          height: 300px;
+        }
+      </style>
+      <div id='container'></div>
+  )HTML");
+
+  LayoutUnit kFragmentainerSpaceAvailable(200);
+
+  NGBlockNode* node = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  auto* space = ConstructConstraintSpace(
+      kHorizontalTopBottom, TextDirection::kLtr,
+      NGLogicalSize(LayoutUnit(1000), NGSizeIndefinite), false,
+      kFragmentainerSpaceAvailable);
+
+  // The first fragment should have ...
+  RefPtr<const NGPhysicalFragment> fragment =
+      NGBlockLayoutAlgorithm(node, space).Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_FALSE(fragment->BreakToken()->IsFinished());
+
+  fragment = NGBlockLayoutAlgorithm(node, space,
+                                    toNGBlockBreakToken(fragment->BreakToken()))
+                 .Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(100), fragment->Height());
+  ASSERT_TRUE(fragment->BreakToken()->IsFinished());
+}
+
+TEST_F(NGBlockLayoutAlgorithmTest, InnerChildrenFragmentation) {
+  setBodyInnerHTML(R"HTML(
+      <!DOCTYPE html>
+      <style>
+        #container {
+          width: 150px;
+          padding-top: 20px;
+        }
+        #child1 {
+          height: 200px;
+          margin-bottom: 20px;
+        }
+        #child2 {
+          height: 100px;
+          margin-top: 20px;
+        }
+      </style>
+      <div id='container'>
+        <div id='child1'></div>
+        <div id='child2'></div>
+      </div>
+  )HTML");
+
+  LayoutUnit kFragmentainerSpaceAvailable(200);
+
+  NGBlockNode* node = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  auto* space = ConstructConstraintSpace(
+      kHorizontalTopBottom, TextDirection::kLtr,
+      NGLogicalSize(LayoutUnit(1000), NGSizeIndefinite), false,
+      kFragmentainerSpaceAvailable);
+
+  // The first fragment should have ...
+  RefPtr<const NGPhysicalFragment> fragment =
+      NGBlockLayoutAlgorithm(node, space).Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_FALSE(fragment->BreakToken()->IsFinished());
+
+  FragmentChildIterator iterator(toNGPhysicalBoxFragment(fragment.get()));
+  const NGPhysicalBoxFragment* child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(180), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(20), child->TopOffset());
+
+  EXPECT_FALSE(iterator.NextChild());
+
+  fragment = NGBlockLayoutAlgorithm(node, space,
+                                    toNGBlockBreakToken(fragment->BreakToken()))
+                 .Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(140), fragment->Height());
+  ASSERT_TRUE(fragment->BreakToken()->IsFinished());
+
+  iterator.SetParent(toNGPhysicalBoxFragment(fragment.get()));
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(20), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(100), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(40), child->TopOffset());
+
+  EXPECT_FALSE(iterator.NextChild());
 }
 
+TEST_F(NGBlockLayoutAlgorithmTest, ParallelFlowFragmentation) {
+  setBodyInnerHTML(R"HTML(
+      <!DOCTYPE html>
+      <style>
+        #container {
+          width: 150px;
+        }
+        #float_left {
+          float: left;
+          width: 20px;
+          height: 300px;
+        }
+        #float_right {
+          float: right;
+          width: 50px;
+          height: 500px;
+        }
+        #in_flow {
+          height: 550px;
+        }
+      </style>
+      <div id='container'>
+        <div id='float_left'></div>
+        <div id='float_right'></div>
+        <div id='in_flow'></div>
+      </div>
+  )HTML");
+
+  LayoutUnit kFragmentainerSpaceAvailable(200);
+
+  NGBlockNode* node = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  auto* space = ConstructConstraintSpace(
+      kHorizontalTopBottom, TextDirection::kLtr,
+      NGLogicalSize(LayoutUnit(1000), NGSizeIndefinite), false,
+      kFragmentainerSpaceAvailable);
+
+  // The first fragment should have ...
+  RefPtr<const NGPhysicalFragment> fragment =
+      NGBlockLayoutAlgorithm(node, space).Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_FALSE(fragment->BreakToken()->IsFinished());
+
+  FragmentChildIterator iterator(toNGPhysicalBoxFragment(fragment.get()));
+
+  // #float_left child.
+  const NGPhysicalBoxFragment* child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(20), child->Width());
+  EXPECT_EQ(LayoutUnit(200), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  // #float_right child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(50), child->Width());
+  EXPECT_EQ(LayoutUnit(200), child->Height());
+  EXPECT_EQ(LayoutUnit(100), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  // #in_flow child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(200), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  EXPECT_FALSE(iterator.NextChild());
+
+  fragment = NGBlockLayoutAlgorithm(node, space,
+                                    toNGBlockBreakToken(fragment->BreakToken()))
+                 .Layout();
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_FALSE(fragment->BreakToken()->IsFinished());
+
+  iterator.SetParent(toNGPhysicalBoxFragment(fragment.get()));
+
+  // #float_left child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(20), child->Width());
+  EXPECT_EQ(LayoutUnit(100), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+  EXPECT_TRUE(child->BreakToken()->IsFinished());
+
+  // #float_right child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(50), child->Width());
+  EXPECT_EQ(LayoutUnit(200), child->Height());
+  EXPECT_EQ(LayoutUnit(100), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  // #in_flow child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(200), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  EXPECT_FALSE(iterator.NextChild());
+
+  fragment = NGBlockLayoutAlgorithm(node, space,
+                                    toNGBlockBreakToken(fragment->BreakToken()))
+                 .Layout();
+
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(150), fragment->Height());
+  ASSERT_FALSE(fragment->BreakToken()->IsFinished());
+
+  iterator.SetParent(toNGPhysicalBoxFragment(fragment.get()));
+
+  // #float_right child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(50), child->Width());
+  EXPECT_EQ(LayoutUnit(100), child->Height());
+  EXPECT_EQ(LayoutUnit(100), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  // #in_flow child.
+  child = iterator.NextChild();
+  EXPECT_EQ(LayoutUnit(150), child->Width());
+  EXPECT_EQ(LayoutUnit(150), child->Height());
+  EXPECT_EQ(LayoutUnit(0), child->LeftOffset());
+  EXPECT_EQ(LayoutUnit(0), child->TopOffset());
+
+  EXPECT_FALSE(iterator.NextChild());
+}
+
+// Tests that a block child will fragment if it reaches it's fragmentation line.
+/*TEST_F(NGBlockLayoutAlgorithmTest, NoFragmentation) {
+  setBodyInnerHTML(
+      "<!DOCTYPE html>"
+      "<style>"
+      "  #container {"
+      "    height: 200px;"
+      "    width: 150px;"
+      "  }"
+      "</style>"
+      "<div id='container'>"
+      "</div>");
+
+  LayoutUnit kFragmentainerSpaceAvailable(200);
+
+  NGBlockNode* node = new NGBlockNode(
+      toLayoutBlockFlow(document().getElementById("container")->layoutObject()));
+  auto* space = ConstructConstraintSpace(
+      kHorizontalTopBottom, TextDirection::kLtr,
+      NGLogicalSize(LayoutUnit(1000), NGSizeIndefinite), false,
+kFragmentainerSpaceAvailable);
+
+  RefPtr<const NGPhysicalBoxFragment> fragment = RunBlockLayoutAlgorithm(space,
+node);
+
+  // We should only have one 150x200 fragment with no fragmentation.
+  EXPECT_EQ(LayoutUnit(150), fragment->Width());
+  EXPECT_EQ(LayoutUnit(200), fragment->Height());
+  ASSERT_TRUE(fragment->BreakToken()->IsFinished());
+}*/
+
 // Test case's HTML representation:
 //  <div id="parent" style="columns:2; column-fill:auto; column-gap:10px;
 //                          width:310px; height:100px;">
@@ -1373,7 +1681,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_EmptyBlock) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInOneColumn) {
+TEST_F(NGBlockLayoutAlgorithmTest, BlockInOneColumn) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(2);
@@ -1423,7 +1731,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInOneColumn) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInTwoColumns) {
+TEST_F(NGBlockLayoutAlgorithmTest, BlockInTwoColumns) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(2);
@@ -1482,7 +1790,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInTwoColumns) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInThreeColumns) {
+TEST_F(NGBlockLayoutAlgorithmTest, BlockInThreeColumns) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);
@@ -1550,8 +1858,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_BlockInThreeColumns) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest,
-       DISABLED_ActualColumnCountGreaterThanSpecified) {
+TEST_F(NGBlockLayoutAlgorithmTest, ActualColumnCountGreaterThanSpecified) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(2);
@@ -1620,7 +1927,7 @@ TEST_F(NGBlockLayoutAlgorithmTest,
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_TwoBlocksInTwoColumns) {
+TEST_F(NGBlockLayoutAlgorithmTest, TwoBlocksInTwoColumns) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);
@@ -1698,7 +2005,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_TwoBlocksInTwoColumns) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_OverflowedBlock) {
+TEST_F(NGBlockLayoutAlgorithmTest, OverflowedBlock) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);
@@ -1809,7 +2116,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_OverflowedBlock) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_FloatInOneColumn) {
+TEST_F(NGBlockLayoutAlgorithmTest, FloatInOneColumn) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);
@@ -1861,7 +2168,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_FloatInOneColumn) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_TwoFloatsInOneColumn) {
+TEST_F(NGBlockLayoutAlgorithmTest, TwoFloatsInOneColumn) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);
@@ -1929,7 +2236,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_TwoFloatsInOneColumn) {
 //  </div>
 // TODO(glebl): reenable multicol after new margin collapsing/floats algorithm
 // is checked in.
-TEST_F(NGBlockLayoutAlgorithmTest, DISABLED_TwoFloatsInTwoColumns) {
+TEST_F(NGBlockLayoutAlgorithmTest, TwoFloatsInTwoColumns) {
   // parent
   RefPtr<ComputedStyle> parent_style = ComputedStyle::create();
   parent_style->setColumnCount(3);