[New Multicolumn] Actual support for layout of column-span:all.

Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp

Index: Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp
diff --git a/Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp b/Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp
index 719607c5ca475f7d9268619f57a29b3fdf2d1841..698511dc883ae1025cf5e3b2e974be89f32e443f 100644
--- a/Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp
+++ b/Source/core/rendering/RenderMultiColumnFlowThreadTest.cpp
@@ -237,6 +237,31 @@ TEST_F(MultiColumnRenderingTest, SubtreeWithSpannerBeforeSpanner)
     EXPECT_EQ(flowThread->containingColumnSpannerSet(document().getElementById("outer")->renderer()), nullptr);
 }
 
+TEST_F(MultiColumnRenderingTest, columnSetAtBlockOffset)
+{
+    setMulticolHTML("<div id='mc' style='line-height:100px;'>text<br>text<br>text<br>text<br>text<div id='spanner1'>spanner</div>text<br>text<div id='spanner2'>text<br>text</div>text</div>");
+    RenderMultiColumnFlowThread* flowThread = findFlowThread("mc");
+    EXPECT_EQ(columnSetSignature(flowThread), "cscsc");
+    RenderMultiColumnSet* firstRow = flowThread->firstMultiColumnSet();
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(-10000)), firstRow); // negative overflow
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit()), firstRow);
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(499)), firstRow); // bottom of last line in first row.
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(599)), firstRow); // empty content in last column in first row
+    RenderMultiColumnSet* firstSpanner = firstRow->nextSiblingMultiColumnSet();
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(600)), firstSpanner);
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(699)), firstSpanner);
+    RenderMultiColumnSet* secondRow = firstSpanner->nextSiblingMultiColumnSet();
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(700)), secondRow);
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(899)), secondRow);
+    RenderMultiColumnSet* secondSpanner = secondRow->nextSiblingMultiColumnSet();
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(900)), secondSpanner);
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(1099)), secondSpanner);
+    RenderMultiColumnSet* thirdRow = secondSpanner->nextSiblingMultiColumnSet();
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(1100)), thirdRow);
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(1199)), thirdRow); // bottom of last row
+    EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(10000)), thirdRow); // overflow
+}
+
 } // anonymous namespace
 
 } // namespace blink