Improve code readibility of PaintPropertyTreeBuilder

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilderTest.cpp

 // Copyright 2015 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/LayoutTestHelper.h"
 #include "core/layout/LayoutTreeAsText.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "platform/graphics/paint/GeometryMapper.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
@@ skipping 60 matching lines @@
 
 TEST_F(PaintPropertyTreeBuilderTest, FixedPosition)
 {
     loadTestData("fixed-position.html");
 
     FrameView* frameView = document().view();
 
     // target1 is a fixed-position element inside an absolute-position scrolling element.
     // It should be attached under the viewport to skip scrolling and offset of the parent.
     Element* target1 = document().getElementById("target1");
-    ObjectPaintProperties* target1Properties = target1->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* target1Properties = target1->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(200, 150), target1Properties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(frameView->preTranslation(), target1Properties->paintOffsetTranslation()->parent());
     EXPECT_EQ(target1Properties->paintOffsetTranslation(), target1Properties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(0, 0, 100, 100), target1Properties->overflowClip()->clipRect());
     // Likewise, it inherits clip from the viewport, skipping overflow clip of the scroller.
     EXPECT_EQ(frameView->contentClip(), target1Properties->overflowClip()->parent());
 
     // target2 is a fixed-position element inside a transformed scrolling element.
     // It should be attached under the scrolled box of the transformed element.
     Element* target2 = document().getElementById("target2");
-    ObjectPaintProperties* target2Properties = target2->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* target2Properties = target2->layoutObject()->objectPaintProperties();
     Element* scroller = document().getElementById("scroller");
-    ObjectPaintProperties* scrollerProperties = scroller->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* scrollerProperties = scroller->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(200, 150), target2Properties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(scrollerProperties->scrollTranslation(), target2Properties->paintOffsetTranslation()->parent());
     EXPECT_EQ(target2Properties->paintOffsetTranslation(), target2Properties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(0, 0, 100, 100), target2Properties->overflowClip()->clipRect());
     EXPECT_EQ(scrollerProperties->overflowClip(), target2Properties->overflowClip()->parent());
 
     CHECK_VISUAL_RECT(target1->layoutObject(), frameView->layoutView());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PositionAndScroll)
 {
     loadTestData("position-and-scroll.html");
 
     Element* scroller = document().getElementById("scroller");
     scroller->scrollTo(0, 100);
     FrameView* frameView = document().view();
     frameView->updateAllLifecyclePhases();
-    ObjectPaintProperties* scrollerProperties = scroller->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* scrollerProperties = scroller->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(0, -100), scrollerProperties->scrollTranslation()->matrix());
     EXPECT_EQ(frameView->scrollTranslation(), scrollerProperties->scrollTranslation()->parent());
     EXPECT_EQ(frameView->scrollTranslation(), scrollerProperties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(120, 340, 400, 300), scrollerProperties->overflowClip()->clipRect());
     EXPECT_EQ(frameView->contentClip(), scrollerProperties->overflowClip()->parent());
 
     // The relative-positioned element should have accumulated box offset (exclude scrolling),
     // and should be affected by ancestor scroll transforms.
     Element* relPos = document().getElementById("rel-pos");
-    ObjectPaintProperties* relPosProperties = relPos->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* relPosProperties = relPos->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(680, 1120), relPosProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(scrollerProperties->scrollTranslation(), relPosProperties->paintOffsetTranslation()->parent());
     EXPECT_EQ(relPosProperties->transform(), relPosProperties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(0, 0, 400, 0), relPosProperties->overflowClip()->clipRect());
     EXPECT_EQ(scrollerProperties->overflowClip(), relPosProperties->overflowClip()->parent());
 
     // The absolute-positioned element should not be affected by non-positioned scroller at all.
     Element* absPos = document().getElementById("abs-pos");
-    ObjectPaintProperties* absPosProperties = absPos->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* absPosProperties = absPos->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(123, 456), absPosProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(frameView->scrollTranslation(), absPosProperties->paintOffsetTranslation()->parent());
     EXPECT_EQ(absPosProperties->transform(), absPosProperties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(), absPosProperties->overflowClip()->clipRect());
     EXPECT_EQ(frameView->contentClip(), absPosProperties->overflowClip()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, FrameScrollingTraditional)
 {
     setBodyInnerHTML("<style> body { height: 10000px; } </style>");
 
     document().domWindow()->scrollTo(0, 100);
 
     FrameView* frameView = document().view();
     frameView->updateAllLifecyclePhases();
     EXPECT_EQ(TransformationMatrix(), frameView->preTranslation()->matrix());
     EXPECT_EQ(frameView->rootTransform(), frameView->preTranslation()->parent());
     EXPECT_EQ(nullptr, frameView->rootTransform()->parent());
     EXPECT_EQ(TransformationMatrix().translate(0, -100), frameView->scrollTranslation()->matrix());
     EXPECT_EQ(frameView->preTranslation(), frameView->scrollTranslation()->parent());
     EXPECT_EQ(frameView->preTranslation(), frameView->contentClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(0, 0, 800, 600), frameView->contentClip()->clipRect());
     EXPECT_EQ(frameView->rootClip(), frameView->contentClip()->parent());
     EXPECT_EQ(nullptr, frameView->rootClip()->parent());
 
     LayoutViewItem layoutViewItem = document().layoutViewItem();
-    ObjectPaintProperties* layoutViewProperties = layoutViewItem.objectPaintProperties();
+    const ObjectPaintProperties* layoutViewProperties = layoutViewItem.objectPaintProperties();
     EXPECT_EQ(nullptr, layoutViewProperties->scrollTranslation());
 }
 
 // TODO(trchen): Settings::rootLayerScrolls cannot be switched after main frame being created.
 // Need to set it during test setup. Besides that, the test still won't work because
 // root layer scrolling mode is not compatible with SPv2 at this moment.
 // (Duplicate display item ID for FrameView and LayoutView.)
 TEST_F(PaintPropertyTreeBuilderTest, DISABLED_FrameScrollingRootLayerScrolls)
 {
     document().settings()->setRootLayerScrolls(true);
 
     setBodyInnerHTML("<style> body { height: 10000px; } </style>");
 
     document().domWindow()->scrollTo(0, 100);
 
     FrameView* frameView = document().view();
     frameView->updateAllLifecyclePhases();
     EXPECT_EQ(TransformationMatrix(), frameView->preTranslation()->matrix());
     EXPECT_EQ(nullptr, frameView->preTranslation()->parent());
     EXPECT_EQ(TransformationMatrix(), frameView->scrollTranslation()->matrix());
     EXPECT_EQ(frameView->preTranslation(), frameView->scrollTranslation()->parent());
 
     LayoutViewItem layoutViewItem = document().layoutViewItem();
-    ObjectPaintProperties* layoutViewProperties = layoutViewItem.objectPaintProperties();
+    const ObjectPaintProperties* layoutViewProperties = layoutViewItem.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(0, -100), layoutViewProperties->scrollTranslation()->matrix());
     EXPECT_EQ(frameView->scrollTranslation(), layoutViewProperties->scrollTranslation()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, Perspective)
 {
     loadTestData("perspective.html");
 
     Element* perspective = document().getElementById("perspective");
-    ObjectPaintProperties* perspectiveProperties = perspective->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* perspectiveProperties = perspective->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().applyPerspective(100), perspectiveProperties->perspective()->matrix());
     // The perspective origin is the center of the border box plus accumulated paint offset.
     EXPECT_EQ(FloatPoint3D(250, 250, 0), perspectiveProperties->perspective()->origin());
     EXPECT_EQ(document().view()->scrollTranslation(), perspectiveProperties->perspective()->parent());
 
     // Adding perspective doesn't clear paint offset. The paint offset will be passed down to children.
     Element* inner = document().getElementById("inner");
-    ObjectPaintProperties* innerProperties = inner->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* innerProperties = inner->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(50, 100), innerProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(perspectiveProperties->perspective(), innerProperties->paintOffsetTranslation()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, Transform)
 {
     loadTestData("transform.html");
 
     Element* transform = document().getElementById("transform");
-    ObjectPaintProperties* transformProperties = transform->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* transformProperties = transform->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(123, 456, 789), transformProperties->transform()->matrix());
     EXPECT_EQ(FloatPoint3D(200, 150, 0), transformProperties->transform()->origin());
     EXPECT_EQ(transformProperties->paintOffsetTranslation(), transformProperties->transform()->parent());
     EXPECT_EQ(TransformationMatrix().translate(50, 100), transformProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(document().view()->scrollTranslation(), transformProperties->paintOffsetTranslation()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, RelativePositionInline)
 {
     loadTestData("relative-position-inline.html");
 
     Element* inlineBlock = document().getElementById("inline-block");
-    ObjectPaintProperties* inlineBlockProperties = inlineBlock->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* inlineBlockProperties = inlineBlock->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(135, 490), inlineBlockProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(document().view()->scrollTranslation(), inlineBlockProperties->paintOffsetTranslation()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, NestedOpacityEffect)
 {
     setBodyInnerHTML(
         "<div id='nodeWithoutOpacity'>"
         "  <div id='childWithOpacity' style='opacity: 0.5'>"
         "    <div id='grandChildWithoutOpacity'>"
         "      <div id='greatGrandChildWithOpacity' style='opacity: 0.2'/>"
         "    </div>"
         "  </div>"
         "</div>");
 
     LayoutObject& nodeWithoutOpacity = *document().getElementById("nodeWithoutOpacity")->layoutObject();
-    ObjectPaintProperties* nodeWithoutOpacityProperties = nodeWithoutOpacity.objectPaintProperties();
+    const ObjectPaintProperties* nodeWithoutOpacityProperties = nodeWithoutOpacity.objectPaintProperties();
     EXPECT_NE(nullptr, nodeWithoutOpacityProperties);
 
     LayoutObject& childWithOpacity = *document().getElementById("childWithOpacity")->layoutObject();
-    ObjectPaintProperties* childWithOpacityProperties = childWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* childWithOpacityProperties = childWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.5f, childWithOpacityProperties->effect()->opacity());
     // childWithOpacity is the root effect node.
     EXPECT_NE(nullptr, childWithOpacityProperties->effect()->parent());
 
     LayoutObject& grandChildWithoutOpacity = *document().getElementById("grandChildWithoutOpacity")->layoutObject();
     EXPECT_NE(nullptr, grandChildWithoutOpacity.objectPaintProperties());
 
     LayoutObject& greatGrandChildWithOpacity = *document().getElementById("greatGrandChildWithOpacity")->layoutObject();
-    ObjectPaintProperties* greatGrandChildWithOpacityProperties = greatGrandChildWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* greatGrandChildWithOpacityProperties = greatGrandChildWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.2f, greatGrandChildWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(childWithOpacityProperties->effect(), greatGrandChildWithOpacityProperties->effect()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, TransformNodeDoesNotAffectEffectNodes)
 {
     setBodyInnerHTML(
         "<div id='nodeWithOpacity' style='opacity: 0.6'>"
         "  <div id='childWithTransform' style='transform: translate3d(10px, 10px, 0px);'>"
         "    <div id='grandChildWithOpacity' style='opacity: 0.4'/>"
         "  </div>"
         "</div>");
 
     LayoutObject& nodeWithOpacity = *document().getElementById("nodeWithOpacity")->layoutObject();
-    ObjectPaintProperties* nodeWithOpacityProperties = nodeWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* nodeWithOpacityProperties = nodeWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.6f, nodeWithOpacityProperties->effect()->opacity());
     EXPECT_NE(nullptr, nodeWithOpacityProperties->effect()->parent());
     EXPECT_EQ(nullptr, nodeWithOpacityProperties->transform());
 
     LayoutObject& childWithTransform = *document().getElementById("childWithTransform")->layoutObject();
-    ObjectPaintProperties* childWithTransformProperties = childWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* childWithTransformProperties = childWithTransform.objectPaintProperties();
     EXPECT_EQ(nullptr, childWithTransformProperties->effect());
     EXPECT_EQ(TransformationMatrix().translate(10, 10), childWithTransformProperties->transform()->matrix());
 
     LayoutObject& grandChildWithOpacity = *document().getElementById("grandChildWithOpacity")->layoutObject();
-    ObjectPaintProperties* grandChildWithOpacityProperties = grandChildWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* grandChildWithOpacityProperties = grandChildWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.4f, grandChildWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(nodeWithOpacityProperties->effect(), grandChildWithOpacityProperties->effect()->parent());
     EXPECT_EQ(nullptr, grandChildWithOpacityProperties->transform());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, EffectNodesAcrossStackingContext)
 {
     setBodyInnerHTML(
         "<div id='nodeWithOpacity' style='opacity: 0.6'>"
         "  <div id='childWithStackingContext' style='position:absolute;'>"
         "    <div id='grandChildWithOpacity' style='opacity: 0.4'/>"
         "  </div>"
         "</div>");
 
     LayoutObject& nodeWithOpacity = *document().getElementById("nodeWithOpacity")->layoutObject();
-    ObjectPaintProperties* nodeWithOpacityProperties = nodeWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* nodeWithOpacityProperties = nodeWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.6f, nodeWithOpacityProperties->effect()->opacity());
     EXPECT_NE(nullptr, nodeWithOpacityProperties->effect()->parent());
     EXPECT_EQ(nullptr, nodeWithOpacityProperties->transform());
 
     LayoutObject& childWithStackingContext = *document().getElementById("childWithStackingContext")->layoutObject();
-    ObjectPaintProperties* childWithStackingContextProperties = childWithStackingContext.objectPaintProperties();
+    const ObjectPaintProperties* childWithStackingContextProperties = childWithStackingContext.objectPaintProperties();
     EXPECT_EQ(nullptr, childWithStackingContextProperties->effect());
     EXPECT_EQ(nullptr, childWithStackingContextProperties->transform());
 
     LayoutObject& grandChildWithOpacity = *document().getElementById("grandChildWithOpacity")->layoutObject();
-    ObjectPaintProperties* grandChildWithOpacityProperties = grandChildWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* grandChildWithOpacityProperties = grandChildWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.4f, grandChildWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(nodeWithOpacityProperties->effect(), grandChildWithOpacityProperties->effect()->parent());
     EXPECT_EQ(nullptr, grandChildWithOpacityProperties->transform());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, EffectNodesInSVG)
 {
     setBodyInnerHTML(
         "<svg id='svgRoot'>"
         "  <g id='groupWithOpacity' opacity='0.6'>"
         "    <rect id='rectWithoutOpacity' />"
         "    <rect id='rectWithOpacity' opacity='0.4' />"
         "    <text id='textWithOpacity' opacity='0.2'>"
         "      <tspan id='tspanWithOpacity' opacity='0.1' />"
         "    </text>"
         "  </g>"
         "</svg>");
 
     LayoutObject& groupWithOpacity = *document().getElementById("groupWithOpacity")->layoutObject();
-    ObjectPaintProperties* groupWithOpacityProperties = groupWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* groupWithOpacityProperties = groupWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.6f, groupWithOpacityProperties->effect()->opacity());
     EXPECT_NE(nullptr, groupWithOpacityProperties->effect()->parent());
 
     LayoutObject& rectWithoutOpacity = *document().getElementById("rectWithoutOpacity")->layoutObject();
-    ObjectPaintProperties* rectWithoutOpacityProperties = rectWithoutOpacity.objectPaintProperties();
+    const ObjectPaintProperties* rectWithoutOpacityProperties = rectWithoutOpacity.objectPaintProperties();
     EXPECT_EQ(nullptr, rectWithoutOpacityProperties);
 
     LayoutObject& rectWithOpacity = *document().getElementById("rectWithOpacity")->layoutObject();
-    ObjectPaintProperties* rectWithOpacityProperties = rectWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* rectWithOpacityProperties = rectWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.4f, rectWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(groupWithOpacityProperties->effect(), rectWithOpacityProperties->effect()->parent());
 
     // Ensure that opacity nodes are created for LayoutSVGText which inherits from LayoutSVGBlock instead of LayoutSVGModelObject.
     LayoutObject& textWithOpacity = *document().getElementById("textWithOpacity")->layoutObject();
-    ObjectPaintProperties* textWithOpacityProperties = textWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* textWithOpacityProperties = textWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.2f, textWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(groupWithOpacityProperties->effect(), textWithOpacityProperties->effect()->parent());
 
     // Ensure that opacity nodes are created for LayoutSVGTSpan which inherits from LayoutSVGInline instead of LayoutSVGModelObject.
     LayoutObject& tspanWithOpacity = *document().getElementById("tspanWithOpacity")->layoutObject();
-    ObjectPaintProperties* tspanWithOpacityProperties = tspanWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* tspanWithOpacityProperties = tspanWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.1f, tspanWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(textWithOpacityProperties->effect(), tspanWithOpacityProperties->effect()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, EffectNodesAcrossHTMLSVGBoundary)
 {
     setBodyInnerHTML(
         "<div id='divWithOpacity' style='opacity: 0.2;'>"
         "  <svg id='svgRootWithOpacity' style='opacity: 0.3;'>"
         "    <rect id='rectWithOpacity' opacity='0.4' />"
         "  </svg>"
         "</div>");
 
     LayoutObject& divWithOpacity = *document().getElementById("divWithOpacity")->layoutObject();
-    ObjectPaintProperties* divWithOpacityProperties = divWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* divWithOpacityProperties = divWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.2f, divWithOpacityProperties->effect()->opacity());
     EXPECT_NE(nullptr, divWithOpacityProperties->effect()->parent());
 
     LayoutObject& svgRootWithOpacity = *document().getElementById("svgRootWithOpacity")->layoutObject();
-    ObjectPaintProperties* svgRootWithOpacityProperties = svgRootWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* svgRootWithOpacityProperties = svgRootWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.3f, svgRootWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(divWithOpacityProperties->effect(), svgRootWithOpacityProperties->effect()->parent());
 
     LayoutObject& rectWithOpacity = *document().getElementById("rectWithOpacity")->layoutObject();
-    ObjectPaintProperties* rectWithOpacityProperties = rectWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* rectWithOpacityProperties = rectWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.4f, rectWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(svgRootWithOpacityProperties->effect(), rectWithOpacityProperties->effect()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, EffectNodesAcrossSVGHTMLBoundary)
 {
     setBodyInnerHTML(
         "<svg id='svgRootWithOpacity' style='opacity: 0.3;'>"
         "  <foreignObject id='foreignObjectWithOpacity' opacity='0.4'>"
         "    <body>"
         "      <span id='spanWithOpacity' style='opacity: 0.5'/>"
         "    </body>"
         "  </foreignObject>"
         "</svg>");
 
     LayoutObject& svgRootWithOpacity = *document().getElementById("svgRootWithOpacity")->layoutObject();
-    ObjectPaintProperties* svgRootWithOpacityProperties = svgRootWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* svgRootWithOpacityProperties = svgRootWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.3f, svgRootWithOpacityProperties->effect()->opacity());
     EXPECT_NE(nullptr, svgRootWithOpacityProperties->effect()->parent());
 
     LayoutObject& foreignObjectWithOpacity = *document().getElementById("foreignObjectWithOpacity")->layoutObject();
-    ObjectPaintProperties* foreignObjectWithOpacityProperties = foreignObjectWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* foreignObjectWithOpacityProperties = foreignObjectWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.4f, foreignObjectWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(svgRootWithOpacityProperties->effect(), foreignObjectWithOpacityProperties->effect()->parent());
 
     LayoutObject& spanWithOpacity = *document().getElementById("spanWithOpacity")->layoutObject();
-    ObjectPaintProperties* spanWithOpacityProperties = spanWithOpacity.objectPaintProperties();
+    const ObjectPaintProperties* spanWithOpacityProperties = spanWithOpacity.objectPaintProperties();
     EXPECT_EQ(0.5f, spanWithOpacityProperties->effect()->opacity());
     EXPECT_EQ(foreignObjectWithOpacityProperties->effect(), spanWithOpacityProperties->effect()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, TransformNodesInSVG)
 {
     setBodyInnerHTML(
         "<style>"
         "  body {"
         "    margin: 0px;"
         "  }"
         "  svg {"
         "    margin-left: 50px;"
         "    transform: translate3d(1px, 2px, 3px);"
         "    position: absolute;"
         "    left: 20px;"
         "    top: 25px;"
         "  }"
         "  rect {"
         "    transform: translate(100px, 100px) rotate(45deg);"
         "    transform-origin: 50px 25px;"
         "  }"
         "</style>"
         "<svg id='svgRootWith3dTransform' width='100px' height='100px'>"
         "  <rect id='rectWith2dTransform' width='100px' height='100px' />"
         "</svg>");
 
     LayoutObject& svgRootWith3dTransform = *document().getElementById("svgRootWith3dTransform")->layoutObject();
-    ObjectPaintProperties* svgRootWith3dTransformProperties = svgRootWith3dTransform.objectPaintProperties();
+    const ObjectPaintProperties* svgRootWith3dTransformProperties = svgRootWith3dTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(1, 2, 3), svgRootWith3dTransformProperties->transform()->matrix());
     EXPECT_EQ(FloatPoint3D(50, 50, 0), svgRootWith3dTransformProperties->transform()->origin());
     EXPECT_EQ(svgRootWith3dTransformProperties->paintOffsetTranslation(), svgRootWith3dTransformProperties->transform()->parent());
     EXPECT_EQ(TransformationMatrix().translate(70, 25), svgRootWith3dTransformProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(document().view()->scrollTranslation(), svgRootWith3dTransformProperties->paintOffsetTranslation()->parent());
 
     LayoutObject& rectWith2dTransform = *document().getElementById("rectWith2dTransform")->layoutObject();
-    ObjectPaintProperties* rectWith2dTransformProperties = rectWith2dTransform.objectPaintProperties();
+    const ObjectPaintProperties* rectWith2dTransformProperties = rectWith2dTransform.objectPaintProperties();
     TransformationMatrix matrix;
     matrix.translate(100, 100);
     matrix.rotate(45);
     // SVG's transform origin is baked into the transform.
     matrix.applyTransformOrigin(50, 25, 0);
     EXPECT_EQ(matrix, rectWith2dTransformProperties->transform()->matrix());
     EXPECT_EQ(FloatPoint3D(0, 0, 0), rectWith2dTransformProperties->transform()->origin());
     // SVG does not use paint offset.
     EXPECT_EQ(nullptr, rectWith2dTransformProperties->paintOffsetTranslation());
 }
@@ skipping 11 matching lines @@
         "  }"
         "  rect {"
         "    transform: translate(100px, 100px);"
         "  }"
         "</style>"
         "<svg id='svgWithViewBox' width='100px' height='100px' viewBox='50 50 100 100'>"
         "  <rect id='rect' width='100px' height='100px' />"
         "</svg>");
 
     LayoutObject& svgWithViewBox = *document().getElementById("svgWithViewBox")->layoutObject();
-    ObjectPaintProperties* svgWithViewBoxProperties = svgWithViewBox.objectPaintProperties();
+    const ObjectPaintProperties* svgWithViewBoxProperties = svgWithViewBox.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(1, 2, 3), svgWithViewBoxProperties->transform()->matrix());
     EXPECT_EQ(TransformationMatrix().translate(-50, -50), svgWithViewBoxProperties->svgLocalToBorderBoxTransform()->matrix());
     EXPECT_EQ(svgWithViewBoxProperties->svgLocalToBorderBoxTransform()->parent(), svgWithViewBoxProperties->transform());
 
     LayoutObject& rect = *document().getElementById("rect")->layoutObject();
-    ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
+    const ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(100, 100), rectProperties->transform()->matrix());
     EXPECT_EQ(svgWithViewBoxProperties->svgLocalToBorderBoxTransform(), rectProperties->transform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, SVGRootPaintOffsetTransformNode)
 {
     setBodyInnerHTML(
         "<style>body { margin: 0px; } </style>"
         "<svg id='svg' style='margin-left: 50px; margin-top: 25px; width: 100px; height: 100px;' />");
 
     LayoutObject& svg = *document().getElementById("svg")->layoutObject();
-    ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
+    const ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
     // Ensure that a paint offset transform is not unnecessarily emitted.
     EXPECT_EQ(nullptr, svgProperties->paintOffsetTranslation());
     EXPECT_EQ(TransformationMatrix().translate(50, 25), svgProperties->svgLocalToBorderBoxTransform()->matrix());
     EXPECT_EQ(document().view()->scrollTranslation(), svgProperties->svgLocalToBorderBoxTransform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, SVGRootLocalToBorderBoxTransformNode)
 {
     setBodyInnerHTML(
         "<style>"
         "  body { margin: 0px; }"
         "  svg { margin-left: 2px; margin-top: 3px; transform: translate(5px, 7px); border: 11px solid green; }"
         "</style>"
         "<svg id='svg' width='100px' height='100px' viewBox='0 0 13 13'>"
         "  <rect id='rect' transform='translate(17 19)' />"
         "</svg>");
 
     LayoutObject& svg = *document().getElementById("svg")->layoutObject();
-    ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
+    const ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(2, 3), svgProperties->paintOffsetTranslation()->matrix());
     EXPECT_EQ(TransformationMatrix().translate(5, 7), svgProperties->transform()->matrix());
     EXPECT_EQ(TransformationMatrix().translate(11, 11).scale(100.0 / 13.0), svgProperties->svgLocalToBorderBoxTransform()->matrix());
     EXPECT_EQ(svgProperties->paintOffsetTranslation(), svgProperties->transform()->parent());
     EXPECT_EQ(svgProperties->transform(), svgProperties->svgLocalToBorderBoxTransform()->parent());
 
     // Ensure the rect's transform is a child of the local to border box transform.
     LayoutObject& rect = *document().getElementById("rect")->layoutObject();
-    ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
+    const ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(17, 19), rectProperties->transform()->matrix());
     EXPECT_EQ(svgProperties->svgLocalToBorderBoxTransform(), rectProperties->transform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, SVGNestedViewboxTransforms)
 {
     setBodyInnerHTML(
         "<style>body { margin: 0px; } </style>"
         "<svg id='svg' width='100px' height='100px' viewBox='0 0 50 50' style='transform: translate(11px, 11px);'>"
         "  <svg id='nestedSvg' width='50px' height='50px' viewBox='0 0 5 5'>"
         "    <rect id='rect' transform='translate(13 13)' />"
         "  </svg>"
         "</svg>");
 
     LayoutObject& svg = *document().getElementById("svg")->layoutObject();
-    ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
+    const ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(11, 11), svgProperties->transform()->matrix());
     EXPECT_EQ(TransformationMatrix().scale(2), svgProperties->svgLocalToBorderBoxTransform()->matrix());
 
     LayoutObject& nestedSvg = *document().getElementById("nestedSvg")->layoutObject();
-    ObjectPaintProperties* nestedSvgProperties = nestedSvg.objectPaintProperties();
+    const ObjectPaintProperties* nestedSvgProperties = nestedSvg.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().scale(10), nestedSvgProperties->transform()->matrix());
     EXPECT_EQ(nullptr, nestedSvgProperties->svgLocalToBorderBoxTransform());
     EXPECT_EQ(svgProperties->svgLocalToBorderBoxTransform(), nestedSvgProperties->transform()->parent());
 
     LayoutObject& rect = *document().getElementById("rect")->layoutObject();
-    ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
+    const ObjectPaintProperties* rectProperties = rect.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(13, 13), rectProperties->transform()->matrix());
     EXPECT_EQ(nestedSvgProperties->transform(), rectProperties->transform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, TransformNodesAcrossSVGHTMLBoundary)
 {
     setBodyInnerHTML(
         "<style> body { margin: 0px; } </style>"
         "<svg id='svgWithTransform' style='transform: translate3d(1px, 2px, 3px);'>"
         "  <foreignObject>"
         "    <body>"
         "      <div id='divWithTransform' style='transform: translate3d(3px, 4px, 5px);'></div>"
         "    </body>"
         "  </foreignObject>"
         "</svg>");
 
     LayoutObject& svgWithTransform = *document().getElementById("svgWithTransform")->layoutObject();
-    ObjectPaintProperties* svgWithTransformProperties = svgWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* svgWithTransformProperties = svgWithTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(1, 2, 3), svgWithTransformProperties->transform()->matrix());
 
     LayoutObject& divWithTransform = *document().getElementById("divWithTransform")->layoutObject();
-    ObjectPaintProperties* divWithTransformProperties = divWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* divWithTransformProperties = divWithTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(3, 4, 5), divWithTransformProperties->transform()->matrix());
     // Ensure the div's transform node is a child of the svg's transform node.
     EXPECT_EQ(svgWithTransformProperties->transform(), divWithTransformProperties->transform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, FixedTransformAncestorAcrossSVGHTMLBoundary)
 {
     setBodyInnerHTML(
         "<style> body { margin: 0px; } </style>"
         "<svg id='svg' style='transform: translate3d(1px, 2px, 3px);'>"
         "  <g id='container' transform='translate(20 30)'>"
         "    <foreignObject>"
         "      <body>"
         "        <div id='fixed' style='position: fixed; left: 200px; top: 150px;'></div>"
         "      </body>"
         "    </foreignObject>"
         "  </g>"
         "</svg>");
 
     LayoutObject& svg = *document().getElementById("svg")->layoutObject();
-    ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
+    const ObjectPaintProperties* svgProperties = svg.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(1, 2, 3), svgProperties->transform()->matrix());
 
     LayoutObject& container = *document().getElementById("container")->layoutObject();
-    ObjectPaintProperties* containerProperties = container.objectPaintProperties();
+    const ObjectPaintProperties* containerProperties = container.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(20, 30), containerProperties->transform()->matrix());
     EXPECT_EQ(svgProperties->transform(), containerProperties->transform()->parent());
 
     Element* fixed = document().getElementById("fixed");
-    ObjectPaintProperties* fixedProperties = fixed->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* fixedProperties = fixed->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(200, 150), fixedProperties->paintOffsetTranslation()->matrix());
     // Ensure the fixed position element is rooted at the nearest transform container.
     EXPECT_EQ(containerProperties->transform(), fixedProperties->paintOffsetTranslation()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, ControlClip)
 {
     setBodyInnerHTML(
         "<style>"
         "  body {"
         "    margin: 0;"
         "  }"
         "  input {"
         "    border-width: 5px;"
         "    padding: 0;"
         "  }"
         "</style>"
         "<input id='button' type='button' style='width:345px; height:123px' value='some text'/>");
 
     FrameView* frameView = document().view();
     LayoutObject& button = *document().getElementById("button")->layoutObject();
-    ObjectPaintProperties* buttonProperties = button.objectPaintProperties();
+    const ObjectPaintProperties* buttonProperties = button.objectPaintProperties();
     EXPECT_EQ(frameView->scrollTranslation(), buttonProperties->overflowClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(5, 5, 335, 113), buttonProperties->overflowClip()->clipRect());
     EXPECT_EQ(frameView->contentClip(), buttonProperties->overflowClip()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, BorderRadiusClip)
 {
     setBodyInnerHTML(
         "<style>"
         " body {"
         "   margin: 0px;"
         " }"
         " #div {"
         "   border-radius: 12px 34px 56px 78px;"
         "   border-top: 45px solid;"
         "   border-right: 50px solid;"
         "   border-bottom: 55px solid;"
         "   border-left: 60px solid;"
         "   width: 500px;"
         "   height: 400px;"
         "   overflow: scroll;"
         " }"
         "</style>"
         "<div id='div'></div>");
 
     FrameView* frameView = document().view();
     LayoutObject& div = *document().getElementById("div")->layoutObject();
-    ObjectPaintProperties* divProperties = div.objectPaintProperties();
+    const ObjectPaintProperties* divProperties = div.objectPaintProperties();
     EXPECT_EQ(frameView->scrollTranslation(), divProperties->overflowClip()->localTransformSpace());
     // The overflow clip rect includes only the padding box.
     // padding box = border box(500+60+50, 400+45+55) - border outset(60+50, 45+55) - scrollbars(15, 15)
     EXPECT_EQ(FloatRoundedRect(60, 45, 500, 400), divProperties->overflowClip()->clipRect());
     const ClipPaintPropertyNode* borderRadiusClip = divProperties->overflowClip()->parent();
     EXPECT_EQ(frameView->scrollTranslation(), borderRadiusClip->localTransformSpace());
     // The border radius clip is the area enclosed by inner border edge, including the scrollbars.
     // As the border-radius is specified in outer radius, the inner radius is calculated by:
     // inner radius = max(outer radius - border width, 0)
     // In the case that two adjacent borders have different width, the inner radius of the corner
@@ skipping 13 matching lines @@
 {
     setBodyInnerHTML(
         "<style>body { margin: 0; }</style>"
         "<div id='divWithTransform' style='transform: translate3d(1px, 2px, 3px);'>"
         "  <iframe id='frame'></iframe>"
         "</div>");
     Document& frameDocument = setupChildIframe("frame", "<style>body { margin: 0; }</style><div id='transform' style='transform: translate3d(4px, 5px, 6px);'></div>");
     document().view()->updateAllLifecyclePhases();
 
     LayoutObject& divWithTransform = *document().getElementById("divWithTransform")->layoutObject();
-    ObjectPaintProperties* divWithTransformProperties = divWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* divWithTransformProperties = divWithTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(1, 2, 3), divWithTransformProperties->transform()->matrix());
 
     LayoutObject* innerDivWithTransform = frameDocument.getElementById("transform")->layoutObject();
-    ObjectPaintProperties* innerDivWithTransformProperties = innerDivWithTransform->objectPaintProperties();
+    const ObjectPaintProperties* innerDivWithTransformProperties = innerDivWithTransform->objectPaintProperties();
     auto* innerDivTransform = innerDivWithTransformProperties->transform();
     EXPECT_EQ(TransformationMatrix().translate3d(4, 5, 6), innerDivTransform->matrix());
 
     // Ensure that the inner div's transform is correctly rooted in the root frame's transform tree.
     // This asserts that we have the following tree structure:
     // ...
     //   Transform transform=translation=1.000000,2.000000,3.000000
     //     PreTranslation transform=translation=2.000000,2.000000,0.000000
     //       ScrollTranslation transform=translation=0.000000,0.000000,0.000000
     //         Transform transform=translation=4.000000,5.000000,6.000000
@@ skipping 52 matching lines @@
     // the painting ancestors.
     setBodyInnerHTML(
         "<style>body { margin: 0; }</style>"
         "<div id='scroller' style='overflow:scroll; width:400px; height:300px;'>"
         "  <div id='child' style='position:relative;'></div>"
         "  <div style='height:10000px;'></div>"
         "</div>"
     );
 
     LayoutObject& scroller = *document().getElementById("scroller")->layoutObject();
-    ObjectPaintProperties* scrollerProperties = scroller.objectPaintProperties();
+    const ObjectPaintProperties* scrollerProperties = scroller.objectPaintProperties();
     LayoutObject& child = *document().getElementById("child")->layoutObject();
-    ObjectPaintProperties* childProperties = child.objectPaintProperties();
+    const ObjectPaintProperties* childProperties = child.objectPaintProperties();
 
     EXPECT_EQ(scrollerProperties->overflowClip(), childProperties->localBorderBoxProperties()->propertyTreeState.clip);
     EXPECT_EQ(scrollerProperties->scrollTranslation(), childProperties->localBorderBoxProperties()->propertyTreeState.transform);
     EXPECT_NE(nullptr, childProperties->localBorderBoxProperties()->propertyTreeState.effect);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, TreeContextUnclipFromParentStackingContext)
 {
     // This test verifies the tree builder correctly computes and records the property tree context
     // for a (pseudo) stacking context that has a scrolling painting ancestor that is not its
     // containing block (thus should not be scrolled by it).
 
     setBodyInnerHTML(
         "<style>body { margin: 0; }</style>"
         "<div id='scroller' style='overflow:scroll; opacity:0.5;'>"
         "  <div id='child' style='position:absolute; left:0; top:0;'></div>"
         "  <div style='height:10000px;'></div>"
         "</div>"
     );
 
     FrameView* frameView = document().view();
     LayoutObject& scroller = *document().getElementById("scroller")->layoutObject();
-    ObjectPaintProperties* scrollerProperties = scroller.objectPaintProperties();
+    const ObjectPaintProperties* scrollerProperties = scroller.objectPaintProperties();
     LayoutObject& child = *document().getElementById("child")->layoutObject();
-    ObjectPaintProperties* childProperties = child.objectPaintProperties();
+    const ObjectPaintProperties* childProperties = child.objectPaintProperties();
 
     EXPECT_EQ(frameView->contentClip(), childProperties->localBorderBoxProperties()->propertyTreeState.clip);
     EXPECT_EQ(frameView->scrollTranslation(), childProperties->localBorderBoxProperties()->propertyTreeState.transform);
     EXPECT_EQ(scrollerProperties->effect(), childProperties->localBorderBoxProperties()->propertyTreeState.effect);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, TableCellLayoutLocation)
 {
     // This test verifies that the border box space of a table cell is being correctly computed.
     // Table cells have weird location adjustment in our layout/paint implementation.
@@ skipping 20 matching lines @@
         "  }"
         "</style>"
         "<table>"
         "  <tr><td></td><td></td></tr>"
         "  <tr><td></td><td><div id='target'></div></td></tr>"
         "</table>"
     );
 
     FrameView* frameView = document().view();
     LayoutObject& target = *document().getElementById("target")->layoutObject();
-    ObjectPaintProperties* targetProperties = target.objectPaintProperties();
+    const ObjectPaintProperties* targetProperties = target.objectPaintProperties();
 
     EXPECT_EQ(LayoutPoint(170, 170), targetProperties->localBorderBoxProperties()->paintOffset);
     EXPECT_EQ(frameView->scrollTranslation(), targetProperties->localBorderBoxProperties()->propertyTreeState.transform);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, CSSClipFixedPositionDescendant)
 {
     // This test verifies that clip tree hierarchy being generated correctly for the hard case
     // such that a fixed position element getting clipped by an absolute position CSS clip.
     setBodyInnerHTML(
@@ skipping 14 matching lines @@
         "</style>"
         "<div id='clip'><div id='fixed'></div></div>"
     );
     LayoutRect localClipRect(40, 10, 40, 60);
     LayoutRect absoluteClipRect = localClipRect;
     absoluteClipRect.move(123, 456);
 
     FrameView* frameView = document().view();
 
     LayoutObject& clip = *document().getElementById("clip")->layoutObject();
-    ObjectPaintProperties* clipProperties = clip.objectPaintProperties();
+    const ObjectPaintProperties* clipProperties = clip.objectPaintProperties();
     EXPECT_EQ(frameView->contentClip(), clipProperties->cssClip()->parent());
     EXPECT_EQ(frameView->scrollTranslation(), clipProperties->cssClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(FloatRect(absoluteClipRect)), clipProperties->cssClip()->clipRect());
 
     LayoutObject& fixed = *document().getElementById("fixed")->layoutObject();
-    ObjectPaintProperties* fixedProperties = fixed.objectPaintProperties();
+    const ObjectPaintProperties* fixedProperties = fixed.objectPaintProperties();
     EXPECT_EQ(clipProperties->cssClip(), fixedProperties->localBorderBoxProperties()->propertyTreeState.clip);
     EXPECT_EQ(frameView->preTranslation(), fixedProperties->localBorderBoxProperties()->propertyTreeState.transform->parent());
     EXPECT_EQ(TransformationMatrix().translate(654, 321), fixedProperties->localBorderBoxProperties()->propertyTreeState.transform->matrix());
     EXPECT_EQ(LayoutPoint(), fixedProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, CSSClipFixedPositionDescendantNonShared)
 {
     // This test is similar to CSSClipFixedPositionDescendant above, except that
     // now we have a parent overflow clip that should be escaped by the fixed descendant.
@@ skipping 24 matching lines @@
         "</style>"
         "<div id='overflow'><div id='clip'><div id='fixed'></div></div></div>"
     );
     LayoutRect localClipRect(40, 10, 40, 60);
     LayoutRect absoluteClipRect = localClipRect;
     absoluteClipRect.move(123, 456);
 
     FrameView* frameView = document().view();
 
     LayoutObject& overflow = *document().getElementById("overflow")->layoutObject();
-    ObjectPaintProperties* overflowProperties = overflow.objectPaintProperties();
+    const ObjectPaintProperties* overflowProperties = overflow.objectPaintProperties();
     EXPECT_EQ(frameView->contentClip(), overflowProperties->overflowClip()->parent());
     EXPECT_EQ(frameView->scrollTranslation(), overflowProperties->scrollTranslation()->parent());
 
     LayoutObject& clip = *document().getElementById("clip")->layoutObject();
-    ObjectPaintProperties* clipProperties = clip.objectPaintProperties();
+    const ObjectPaintProperties* clipProperties = clip.objectPaintProperties();
     EXPECT_EQ(overflowProperties->overflowClip(), clipProperties->cssClip()->parent());
     EXPECT_EQ(overflowProperties->scrollTranslation(), clipProperties->cssClip()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(FloatRect(absoluteClipRect)), clipProperties->cssClip()->clipRect());
     EXPECT_EQ(frameView->contentClip(), clipProperties->cssClipFixedPosition()->parent());
     EXPECT_EQ(overflowProperties->scrollTranslation(), clipProperties->cssClipFixedPosition()->localTransformSpace());
     EXPECT_EQ(FloatRoundedRect(FloatRect(absoluteClipRect)), clipProperties->cssClipFixedPosition()->clipRect());
 
     LayoutObject& fixed = *document().getElementById("fixed")->layoutObject();
-    ObjectPaintProperties* fixedProperties = fixed.objectPaintProperties();
+    const ObjectPaintProperties* fixedProperties = fixed.objectPaintProperties();
     EXPECT_EQ(clipProperties->cssClipFixedPosition(), fixedProperties->localBorderBoxProperties()->propertyTreeState.clip);
     EXPECT_EQ(frameView->preTranslation(), fixedProperties->localBorderBoxProperties()->propertyTreeState.transform->parent());
     EXPECT_EQ(TransformationMatrix().translate(654, 321), fixedProperties->localBorderBoxProperties()->propertyTreeState.transform->matrix());
     EXPECT_EQ(LayoutPoint(), fixedProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, ColumnSpannerUnderRelativePositioned)
 {
     setBodyInnerHTML(
         "<div style='columns: 3; position: absolute; top: 44px; left: 55px;'>"
@@ skipping 12 matching lines @@
     setBodyInnerHTML(
         "<style>"
         "  * { margin: 0; }"
         "  div { position: absolute; }"
         "</style>"
         "<div id='a' style='width: 70px; height: 70px; left: 0.1px; top: 0.3px;'>"
         "  <div id='b' style='width: 40px; height: 40px; left: 0.5px; top: 11.1px;'></div>"
         "</div>"
     );
 
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
     LayoutPoint aPaintOffset = LayoutPoint(FloatPoint(0.1, 0.3));
     EXPECT_EQ(aPaintOffset, aProperties->localBorderBoxProperties()->paintOffset);
 
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     LayoutPoint bPaintOffset = aPaintOffset + LayoutPoint(FloatPoint(0.5, 11.1));
     EXPECT_EQ(bPaintOffset, bProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PaintOffsetWithBasicPixelSnapping)
 {
     setBodyInnerHTML(
         "<style>"
         "  * { margin: 0; }"
         "  div { position: relative; }"
         "</style>"
         "<div id='a' style='width: 70px; height: 70px; left: 0.3px; top: 0.3px;'>"
         "  <div id='b' style='width: 40px; height: 40px; transform: translateZ(0);'>"
         "    <div id='c' style='width: 40px; height: 40px; left: 0.1px; top: 0.1px;'></div>"
         "  </div>"
         "</div>"
     );
 
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(0, 0, 0), bProperties->transform()->matrix());
     // The paint offset transform should be snapped from (0.3,0.3) to (0,0).
     EXPECT_EQ(TransformationMatrix().translate(0, 0), bProperties->transform()->parent()->matrix());
     // The residual subpixel adjustment should be (0.3,0.3) - (0,0) = (0.3,0.3).
     LayoutPoint subpixelAccumulation = LayoutPoint(FloatPoint(0.3, 0.3));
     EXPECT_EQ(subpixelAccumulation, bProperties->localBorderBoxProperties()->paintOffset);
 
     // c should be painted starting at subpixelAccumulation + (0.1,0.1) = (0.4,0.4).
     LayoutPoint cPaintOffset = subpixelAccumulation + LayoutPoint(FloatPoint(0.1, 0.1));
-    ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(cPaintOffset, cProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PaintOffsetWithPixelSnappingThroughTransform)
 {
     setBodyInnerHTML(
         "<style>"
         "  * { margin: 0; }"
         "  div { position: relative; }"
         "</style>"
         "<div id='a' style='width: 70px; height: 70px; left: 0.7px; top: 0.7px;'>"
         "  <div id='b' style='width: 40px; height: 40px; transform: translateZ(0);'>"
         "    <div id='c' style='width: 40px; height: 40px; left: 0.7px; top: 0.7px;'></div>"
         "  </div>"
         "</div>"
     );
 
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(0, 0, 0), bProperties->transform()->matrix());
     // The paint offset transform should be snapped from (0.7,0.7) to (1,1).
     EXPECT_EQ(TransformationMatrix().translate(1, 1), bProperties->transform()->parent()->matrix());
     // The residual subpixel adjustment should be (0.7,0.7) - (1,1) = (-0.3,-0.3).
     LayoutPoint subpixelAccumulation = LayoutPoint(LayoutPoint(FloatPoint(0.7, 0.7)) - LayoutPoint(1, 1));
     EXPECT_EQ(subpixelAccumulation, bProperties->localBorderBoxProperties()->paintOffset);
 
     // c should be painted starting at subpixelAccumulation + (0.7,0.7) = (0.4,0.4).
     LayoutPoint cPaintOffset = subpixelAccumulation + LayoutPoint(FloatPoint(0.7, 0.7));
-    ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(cPaintOffset, cProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PaintOffsetWithPixelSnappingThroughMultipleTransforms)
 {
     setBodyInnerHTML(
         "<style>"
         "  * { margin: 0; }"
         "  div { position: relative; }"
         "</style>"
         "<div id='a' style='width: 70px; height: 70px; left: 0.7px; top: 0.7px;'>"
         "  <div id='b' style='width: 40px; height: 40px; transform: translate3d(5px, 7px, 0);'>"
         "    <div id='c' style='width: 40px; height: 40px; transform: translate3d(11px, 13px, 0);'>"
         "      <div id='d' style='width: 40px; height: 40px; left: 0.7px; top: 0.7px;'></div>"
         "    </div>"
         "  </div>"
         "</div>"
     );
 
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(5, 7, 0), bProperties->transform()->matrix());
     // The paint offset transform should be snapped from (0.7,0.7) to (1,1).
     EXPECT_EQ(TransformationMatrix().translate(1, 1), bProperties->transform()->parent()->matrix());
     // The residual subpixel adjustment should be (0.7,0.7) - (1,1) = (-0.3,-0.3).
     LayoutPoint subpixelAccumulation = LayoutPoint(LayoutPoint(FloatPoint(0.7, 0.7)) - LayoutPoint(1, 1));
     EXPECT_EQ(subpixelAccumulation, bProperties->localBorderBoxProperties()->paintOffset);
 
-    ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* cProperties = document().getElementById("c")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate3d(11, 13, 0), cProperties->transform()->matrix());
     // The paint offset should be (-0.3,-0.3) but the paint offset transform should still be at
     // (0,0) because it should be snapped.
     EXPECT_EQ(TransformationMatrix().translate(0, 0), cProperties->transform()->parent()->matrix());
     // The residual subpixel adjustment should still be (-0.3,-0.3).
     EXPECT_EQ(subpixelAccumulation, cProperties->localBorderBoxProperties()->paintOffset);
 
     // d should be painted starting at subpixelAccumulation + (0.7,0.7) = (0.4,0.4).
     LayoutPoint dPaintOffset = subpixelAccumulation + LayoutPoint(FloatPoint(0.7, 0.7));
-    ObjectPaintProperties* dProperties = document().getElementById("d")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* dProperties = document().getElementById("d")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(dPaintOffset, dProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PaintOffsetWithPixelSnappingWithFixedPos)
 {
     setBodyInnerHTML(
         "<style>"
         "  * { margin: 0; }"
         "</style>"
         "<div id='a' style='width: 70px; height: 70px; left: 0.7px; position: relative;'>"
         "  <div id='b' style='width: 40px; height: 40px; transform: translateZ(0); position: relative;'>"
         "    <div id='fixed' style='width: 40px; height: 40px; position: fixed;'>"
         "      <div id='d' style='width: 40px; height: 40px; left: 0.7px; position: relative;'></div>"
         "    </div>"
         "  </div>"
         "</div>"
     );
 
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(0, 0), bProperties->transform()->matrix());
     // The paint offset transform should be snapped from (0.7,0) to (1,0).
     EXPECT_EQ(TransformationMatrix().translate(1, 0), bProperties->transform()->parent()->matrix());
     // The residual subpixel adjustment should be (0.7,0) - (1,0) = (-0.3,0).
     LayoutPoint subpixelAccumulation = LayoutPoint(LayoutPoint(FloatPoint(0.7, 0)) - LayoutPoint(1, 0));
     EXPECT_EQ(subpixelAccumulation, bProperties->localBorderBoxProperties()->paintOffset);
 
-    ObjectPaintProperties* fixedProperties = document().getElementById("fixed")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* fixedProperties = document().getElementById("fixed")->layoutObject()->objectPaintProperties();
     // The residual subpixel adjustment should still be (-0.3,0).
     EXPECT_EQ(subpixelAccumulation, fixedProperties->localBorderBoxProperties()->paintOffset);
 
     // d should be painted starting at subpixelAccumulation + (0.7,0) = (0.4,0).
     LayoutPoint dPaintOffset = subpixelAccumulation + LayoutPoint(FloatPoint(0.7, 0));
-    ObjectPaintProperties* dProperties = document().getElementById("d")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* dProperties = document().getElementById("d")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(dPaintOffset, dProperties->localBorderBoxProperties()->paintOffset);
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, SvgPixelSnappingShouldResetPaintOffset)
 {
     setBodyInnerHTML(
         "<svg id='svg' style='position: relative; left: 0.1px; transform: matrix(1, 0, 0, 1, 0, 0);'>"
         "    <rect id='rect' transform='translate(1, 1)'/>"
         "</svg>");
 
     LayoutObject& svgWithTransform = *document().getElementById("svg")->layoutObject();
-    ObjectPaintProperties* svgWithTransformProperties = svgWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* svgWithTransformProperties = svgWithTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix(), svgWithTransformProperties->transform()->matrix());
     EXPECT_EQ(LayoutPoint(FloatPoint(0.1, 0)), svgWithTransformProperties->localBorderBoxProperties()->paintOffset);
     EXPECT_EQ(nullptr, svgWithTransformProperties->svgLocalToBorderBoxTransform());
 
     LayoutObject& rectWithTransform = *document().getElementById("rect")->layoutObject();
-    ObjectPaintProperties* rectWithTransformProperties = rectWithTransform.objectPaintProperties();
+    const ObjectPaintProperties* rectWithTransformProperties = rectWithTransform.objectPaintProperties();
     EXPECT_EQ(TransformationMatrix().translate(1, 1), rectWithTransformProperties->transform()->matrix());
 
     // Ensure there is no PaintOffset transform between the rect and the svg's transform.
     EXPECT_EQ(svgWithTransformProperties->transform(), rectWithTransformProperties->transform()->parent());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, NoRenderingContextByDefault)
 {
     setBodyInnerHTML("<div style=\"transform: translateZ(0)\"></div>");
 
-    ObjectPaintProperties* properties = document().body()->firstChild()->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* properties = document().body()->firstChild()->layoutObject()->objectPaintProperties();
     ASSERT_TRUE(properties->transform());
     EXPECT_FALSE(properties->transform()->hasRenderingContext());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, Preserve3DCreatesSharedRenderingContext)
 {
     setBodyInnerHTML(
         "<div style=\"transform-style: preserve-3d\">"
         "  <div id=\"a\" style=\"transform: translateZ(0)\"></div>"
         "  <div id=\"b\" style=\"transform: translateZ(0)\"></div>"
         "</div>");
 
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     ASSERT_TRUE(aProperties->transform() && bProperties->transform());
     EXPECT_NE(aProperties->transform(), bProperties->transform());
     EXPECT_TRUE(aProperties->transform()->hasRenderingContext());
     EXPECT_TRUE(bProperties->transform()->hasRenderingContext());
     EXPECT_EQ(aProperties->transform()->renderingContextID(), bProperties->transform()->renderingContextID());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, FlatTransformStyleEndsRenderingContext)
 {
     setBodyInnerHTML(
         "<div style=\"transform-style: preserve-3d\">"
         "  <div id=\"a\" style=\"transform: translateZ(0)\">"
         "    <div id=\"b\" style=\"transform: translateZ(0)\"></div>"
         "  </div>"
         "</div>");
 
     ASSERT_FALSE(document().getElementById("a")->layoutObject()->styleRef().preserves3D());
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     ASSERT_TRUE(aProperties->transform() && bProperties->transform());
 
     // #a should participate in a rendering context (due to its parent), but its
     // child #b should not.
     EXPECT_TRUE(aProperties->transform()->hasRenderingContext());
     EXPECT_FALSE(bProperties->transform()->hasRenderingContext());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, NestedRenderingContexts)
 {
     setBodyInnerHTML(
         "<div style=\"transform-style: preserve-3d\">"
         "  <div id=\"a\" style=\"transform: translateZ(0)\">"
         "    <div style=\"transform-style: preserve-3d\">"
         "      <div id=\"b\" style=\"transform: translateZ(0)\">"
         "    </div>"
         "  </div>"
         "</div>");
 
     ASSERT_FALSE(document().getElementById("a")->layoutObject()->styleRef().preserves3D());
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     ASSERT_TRUE(aProperties->transform() && bProperties->transform());
 
     // #a should participate in a rendering context (due to its parent). Its
     // child does preserve 3D, but since #a does not, #a's rendering context is
     // not passed on to its children. Thus #b ends up in a separate rendering
     // context rooted at its parent.
     EXPECT_TRUE(aProperties->transform()->hasRenderingContext());
     EXPECT_TRUE(bProperties->transform()->hasRenderingContext());
     EXPECT_NE(aProperties->transform()->renderingContextID(), bProperties->transform()->renderingContextID());
 }
@@ skipping 60 matching lines @@
 TEST_F(PaintPropertyTreeBuilderTest, PerspectiveIsNotFlattened)
 {
     // It's necessary to make nodes from the one that applies perspective to
     // ones that combine with it preserve 3D. Otherwise, the perspective doesn't
     // do anything.
     setBodyInnerHTML(
         "<div id=\"a\" style=\"perspective: 800px\">"
         "  <div id=\"b\" style=\"transform: translateZ(0)\"></div>"
         "</div>");
 
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     const TransformPaintPropertyNode* aPerspective = aProperties->perspective();
     ASSERT_TRUE(aPerspective);
     const TransformPaintPropertyNode* bTransform = bProperties->transform();
     ASSERT_TRUE(bTransform);
     ASSERT_TRUE(nodeHasAncestor(bTransform, aPerspective));
     EXPECT_FALSE(someNodeFlattensTransform(bTransform, aPerspective));
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, PerspectiveDoesNotEstablishRenderingContext)
 {
     // It's necessary to make nodes from the one that applies perspective to
     // ones that combine with it preserve 3D. Otherwise, the perspective doesn't
     // do anything.
     setBodyInnerHTML(
         "<div id=\"a\" style=\"perspective: 800px\">"
         "  <div id=\"b\" style=\"transform: translateZ(0)\"></div>"
         "</div>");
 
-    ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
-    ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* aProperties = document().getElementById("a")->layoutObject()->objectPaintProperties();
+    const ObjectPaintProperties* bProperties = document().getElementById("b")->layoutObject()->objectPaintProperties();
     const TransformPaintPropertyNode* aPerspective = aProperties->perspective();
     ASSERT_TRUE(aPerspective);
     EXPECT_FALSE(aPerspective->hasRenderingContext());
     const TransformPaintPropertyNode* bTransform = bProperties->transform();
     ASSERT_TRUE(bTransform);
     EXPECT_FALSE(bTransform->hasRenderingContext());
 }
 
 TEST_F(PaintPropertyTreeBuilderTest, CachedProperties)
 {
     setBodyInnerHTML(
         "<div id='a' style='transform: translate(33px, 44px)'>"
         "  <div id='b' style='transform: translate(55px, 66px)'>"
         "    <div id='c' style='transform: translate(77px, 88px)'>C<div>"
         "  </div>"
         "</div>");
 
     Element* a = document().getElementById("a");
-    ObjectPaintProperties* aProperties = a->layoutObject()->objectPaintProperties();
-    TransformPaintPropertyNode* aTransformNode = aProperties->transform();
+    const ObjectPaintProperties* aProperties = a->layoutObject()->objectPaintProperties();
+    const TransformPaintPropertyNode* aTransformNode = aProperties->transform();
     EXPECT_EQ(TransformationMatrix().translate(33, 44), aTransformNode->matrix());
 
     Element* b = document().getElementById("b");
-    ObjectPaintProperties* bProperties = b->layoutObject()->objectPaintProperties();
-    TransformPaintPropertyNode* bTransformNode = bProperties->transform();
+    const ObjectPaintProperties* bProperties = b->layoutObject()->objectPaintProperties();
+    const TransformPaintPropertyNode* bTransformNode = bProperties->transform();
     EXPECT_EQ(TransformationMatrix().translate(55, 66), bTransformNode->matrix());
 
     Element* c = document().getElementById("c");
-    ObjectPaintProperties* cProperties = c->layoutObject()->objectPaintProperties();
-    TransformPaintPropertyNode* cTransformNode = cProperties->transform();
+    const ObjectPaintProperties* cProperties = c->layoutObject()->objectPaintProperties();
+    const TransformPaintPropertyNode* cTransformNode = cProperties->transform();
     EXPECT_EQ(TransformationMatrix().translate(77, 88), cTransformNode->matrix());
 
     // Change transform of b. B's transform node should be a new node with the new value,
     // and a and c's transform nodes should be unchanged (with c's parent adjusted).
     b->setAttribute(HTMLNames::styleAttr, "transform: translate(111px, 222px)");
     document().view()->updateAllLifecyclePhases();
 
     EXPECT_EQ(aProperties, a->layoutObject()->objectPaintProperties());
     EXPECT_EQ(aTransformNode, aProperties->transform());
 
@@ skipping 33 matching lines @@
     bTransformNode = bProperties->transform();
     EXPECT_EQ(TransformationMatrix().translate(4, 5), bTransformNode->matrix());
     EXPECT_EQ(aTransformNode, bTransformNode->parent());
 
     EXPECT_EQ(cProperties, c->layoutObject()->objectPaintProperties());
     EXPECT_EQ(cTransformNode, cProperties->transform());
     EXPECT_EQ(bTransformNode, cTransformNode->parent());
 }
 
 } // namespace blink