Top down version of algorithm to position margins and floats in LayoutNG

third_party/WebKit/Source/core/layout/ng/ng_constraint_space_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_constraint_space.h"
 
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_constraint_space_builder.h"
 #include "core/layout/ng/ng_layout_opportunity_iterator.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 133 matching lines @@
 }
 
 // This test is the same as LayoutOpportunitiesTwoInMiddle with the only
 // difference that NGLayoutOpportunityIterator takes 2 additional arguments:
 // - origin_point that changes the iterator to return Layout Opportunities that
 // lay after the origin point.
 // - leader_point that together with origin_point creates a temporary exclusion
 //
 // Expected:
 //   Layout opportunity iterator generates the next opportunities:
-//   - 1st Start Point (0, 200): 350x150, 250x200
-//   - 3rd Start Point (550, 200): 50x200
-//   - 4th Start Point (0, 300): 600x50, 500x100
+//   - 1st Start Point (0, 200): 350x150, 250x400
+//   - 3rd Start Point (550, 200): 50x400
+//   - 4th Start Point (0, 300): 600x50, 500x300
+//   - 5th Start Point (0, 400): 600x200
 //   All other opportunities that are located before the origin point should be
 //   filtered out.
 TEST(NGConstraintSpaceTest, LayoutOpportunitiesTwoInMiddleWithOriginAndLeader) {
   NGLogicalSize size;
   size.inline_size = LayoutUnit(600);
   size.block_size = LayoutUnit(400);
   auto* space =
       ConstructConstraintSpace(kHorizontalTopBottom, TextDirection::kLtr, size);
   // Add exclusions
   NGExclusion exclusion1;
   exclusion1.rect.size = {/* inline_size */ LayoutUnit(100),
                           /* block_size */ LayoutUnit(100)};
   exclusion1.rect.offset = {/* inline_offset */ LayoutUnit(150),
                             /* block_offset */ LayoutUnit(200)};
   space->AddExclusion(exclusion1);
   NGExclusion exclusion2;
   exclusion2.rect.size = {/* inline_size */ LayoutUnit(50),
                           /* block_size */ LayoutUnit(50)};
   exclusion2.rect.offset = {/* inline_offset */ LayoutUnit(500),
                             /* block_offset */ LayoutUnit(350)};
   space->AddExclusion(exclusion2);
   const NGLogicalOffset origin_point = {LayoutUnit(0), LayoutUnit(200)};
   const NGLogicalOffset leader_point = {LayoutUnit(250), LayoutUnit(300)};
   auto* iterator =
       new NGLayoutOpportunityIterator(space, origin_point, leader_point);
   // 1st Start Point
   EXPECT_EQ("250,200 350x150", OpportunityToString(iterator->Next()));
-  EXPECT_EQ("250,200 250x200", OpportunityToString(iterator->Next()));
+  EXPECT_EQ("250,200 250x400", OpportunityToString(iterator->Next()));
   // 2nd Start Point
-  EXPECT_EQ("550,200 50x200", OpportunityToString(iterator->Next()));
+  EXPECT_EQ("550,200 50x400", OpportunityToString(iterator->Next()));
   // 3rd Start Point
   EXPECT_EQ("0,300 600x50", OpportunityToString(iterator->Next()));
-  EXPECT_EQ("0,300 500x100", OpportunityToString(iterator->Next()));
+  EXPECT_EQ("0,300 500x300", OpportunityToString(iterator->Next()));
+  // 4th Start Point
+  EXPECT_EQ("0,400 600x200", OpportunityToString(iterator->Next()));
+  // TODO(glebl): The opportunity below should not be generated.
+  EXPECT_EQ("250,400 350x200", OpportunityToString(iterator->Next()));
   // Iterator is exhausted.
   EXPECT_EQ("(empty)", OpportunityToString(iterator->Next()));
 }
 // Verifies that Layout Opportunity iterator ignores the exclusion that is not
 // within constraint space.
 //
 // Test case visual representation:
 //
 //         100  200  300  400  500
 //     +----|----|----|----|----|----+
@@ skipping 17 matching lines @@
   exclusion.rect.offset = {/* inline_offset */ LayoutUnit(0),
                            /* block_offset */ LayoutUnit(150)};
   space->AddExclusion(exclusion);
   auto* iterator = space->LayoutOpportunities();
   EXPECT_EQ("0,0 600x100", OpportunityToString(iterator->Next()));
   EXPECT_EQ("(empty)", OpportunityToString(iterator->Next()));
 }
 
 }  // namespace
 }  // namespace blink