Make RenderObject::style() return a const object

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
diff --git a/Source/core/frame/FrameView.cpp b/Source/core/frame/FrameView.cpp
index 27f746bed86e6caa4dd6ac1c737daa4c888f456a..69336ae3f253bd703d93c15b3902310ad780c14f 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -1299,15 +1299,15 @@ void FrameView::viewportConstrainedVisibleContentSizeChanged(bool widthChanged,
 
     for (const auto& viewportConstrainedObject : *m_viewportConstrainedObjects) {
         LayoutObject* renderer = viewportConstrainedObject;
-        LayoutStyle* style = renderer->style();
+        const LayoutStyle& style = renderer->styleRef();
         if (widthChanged) {
-            if (style->width().isFixed() && (style->left().isAuto() || style->right().isAuto()))
+            if (style.width().isFixed() && (style.left().isAuto() || style.right().isAuto()))
                 renderer->setNeedsPositionedMovementLayout();
             else
                 renderer->setNeedsLayoutAndFullPaintInvalidation();
         }
         if (heightChanged) {
-            if (style->height().isFixed() && (style->top().isAuto() || style->bottom().isAuto()))
+            if (style.height().isFixed() && (style.top().isAuto() || style.bottom().isAuto()))
                 renderer->setNeedsPositionedMovementLayout();
             else
                 renderer->setNeedsLayoutAndFullPaintInvalidation();