Need to be inside the flow thread before converting a visual point.

third_party/WebKit/Source/core/layout/MapCoordinatesTest.cpp

 // 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/LayoutInline.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
 #include "platform/geometry/TransformState.h"
 #include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 1009 matching lines @@
   mappedPoint = mapAncestorToLocal(multicol, container, mappedPoint);
   EXPECT_EQ(FloatPoint(6, 6), mappedPoint);
 
   mappedPoint = mapAncestorToLocal(flowThread, multicol, mappedPoint);
   EXPECT_EQ(FloatPoint(-9, -9), mappedPoint);
 
   mappedPoint = mapAncestorToLocal(target, flowThread, mappedPoint);
   EXPECT_EQ(FloatPoint(), mappedPoint);
 }
 
+TEST_P(MapCoordinatesTest, MulticolRtl) {
+  setBodyInnerHTML(
+      "<div id='container' style='columns:3; column-gap:0; column-fill:auto; "
+      "width:300px; height:200px; direction:rtl;'>"
+      "    <div style='height:200px;'></div>"
+      "    <div id='target' style='height:50px;'></div>"
+      "</div>");
+
+  LayoutBox* target = toLayoutBox(getLayoutObjectByElementId("target"));
+  LayoutBox* container = toLayoutBox(getLayoutObjectByElementId("container"));
+
+  FloatPoint mappedPoint = mapLocalToAncestor(target, container, FloatPoint());
+  EXPECT_EQ(FloatPoint(100, 0), mappedPoint);
+  mappedPoint = mapAncestorToLocal(target, container, mappedPoint);
+  EXPECT_EQ(FloatPoint(), mappedPoint);
+
+  // Walk each ancestor in the chain separately, to verify each step on the way.
+  LayoutBox* flowThread = target->parentBox();
+  ASSERT_TRUE(flowThread->isLayoutFlowThread());
+
+  mappedPoint = mapLocalToAncestor(target, flowThread, FloatPoint());
+  EXPECT_EQ(FloatPoint(0, 200), mappedPoint);
+  mappedPoint = mapAncestorToLocal(target, flowThread, mappedPoint);
+  EXPECT_EQ(FloatPoint(), mappedPoint);
+
+  mappedPoint = mapLocalToAncestor(flowThread, container, FloatPoint(0, 200));
+  EXPECT_EQ(FloatPoint(100, 0), mappedPoint);
+  mappedPoint = mapAncestorToLocal(flowThread, container, mappedPoint);
+  EXPECT_EQ(FloatPoint(0, 200), mappedPoint);
+}
+
+TEST_P(MapCoordinatesTest, MulticolWithLargeBorder) {
+  setBodyInnerHTML(
+      "<div id='container' style='columns:3; column-gap:0; column-fill:auto; "
+      "width:300px; height:200px; border:200px solid;'>"
+      "    <div style='height:200px;'></div>"
+      "    <div id='target' style='height:50px;'></div>"
+      "    <div style='height:200px;'></div>"
+      "</div>");
+
+  LayoutBox* target = toLayoutBox(getLayoutObjectByElementId("target"));
+  LayoutBox* container = toLayoutBox(getLayoutObjectByElementId("container"));
+
+  FloatPoint mappedPoint = mapLocalToAncestor(target, container, FloatPoint());
+  EXPECT_EQ(FloatPoint(300, 200), mappedPoint);
+  mappedPoint = mapAncestorToLocal(target, container, mappedPoint);
+  EXPECT_EQ(FloatPoint(), mappedPoint);
+
+  // Walk each ancestor in the chain separately, to verify each step on the way.
+  LayoutBox* flowThread = target->parentBox();
+  ASSERT_TRUE(flowThread->isLayoutFlowThread());
+
+  mappedPoint = mapLocalToAncestor(target, flowThread, FloatPoint());
+  EXPECT_EQ(FloatPoint(0, 200), mappedPoint);
+  mappedPoint = mapAncestorToLocal(target, flowThread, mappedPoint);
+  EXPECT_EQ(FloatPoint(), mappedPoint);
+
+  mappedPoint = mapLocalToAncestor(flowThread, container, FloatPoint(0, 200));
+  EXPECT_EQ(FloatPoint(300, 200), mappedPoint);
+  mappedPoint = mapAncestorToLocal(flowThread, container, mappedPoint);
+  EXPECT_EQ(FloatPoint(0, 200), mappedPoint);
+}
+
 TEST_P(MapCoordinatesTest, FlippedBlocksWritingModeWithText) {
   setBodyInnerHTML(
       "<div style='-webkit-writing-mode:vertical-rl;'>"
       "    <div style='width:13px;'></div>"
       "    <div style='width:200px; height:400px; line-height:50px;'>"
       "        <br id='sibling'>text"
       "    </div>"
       "    <div style='width:5px;'></div>"
       "</div>");
 
@@ skipping 542 matching lines @@
               LayoutUnit::epsilon());
   EXPECT_NEAR(50.0, matrix.projectPoint(FloatPoint(100.0, 50.0)).y(),
               LayoutUnit::epsilon());
   EXPECT_NEAR(25.0, matrix.projectPoint(FloatPoint(50.0, 100.0)).x(),
               LayoutUnit::epsilon());
   EXPECT_NEAR(100.0, matrix.projectPoint(FloatPoint(50.0, 100.0)).y(),
               LayoutUnit::epsilon());
 }
 
 }  // namespace blink