[LFC] Remove unsupported (and broken) LayoutContext::layout codepath

https://bugs.webkit.org/show_bug.cgi?id=260142

Reviewed by Antti Koivisto.

Full LFC codepath has not been maintained for a while now (integration codepath is slowly taking over).

* Source/WebCore/page/LocalFrameViewLayoutContext.cpp:
(WebCore::LocalFrameViewLayoutContext::performLayout):
(WebCore::LocalFrameViewLayoutContext::layoutUsingFormattingContext): Deleted.
* Source/WebCore/page/LocalFrameViewLayoutContext.h:
(WebCore::LocalFrameViewLayoutContext::enablePaintOffsetCache):

Canonical link: https://commits.webkit.org/266895@main

Source/WebCore/page/LocalFrameViewLayoutContext.cpp

@@ -55,38 +55,6 @@ namespace WebCore {
 UpdateScrollInfoAfterLayoutTransaction::UpdateScrollInfoAfterLayoutTransaction() = default;
 UpdateScrollInfoAfterLayoutTransaction::~UpdateScrollInfoAfterLayoutTransaction() = default;
 
-void LocalFrameViewLayoutContext::layoutUsingFormattingContext()
-{
-    if (!frame().settings().layoutFormattingContextEnabled())
-        return;
-    // LocalFrameView::setContentsSize temporary disables layout.
-    if (m_disableSetNeedsLayoutCount)
-        return;
-
-    m_layoutState = nullptr;
-    m_layoutTree = nullptr;
-
-    auto& renderView = *this->renderView();
-    m_layoutTree = Layout::TreeBuilder::buildLayoutTree(renderView);
-    m_layoutState = makeUnique<Layout::LayoutState>(*document(), m_layoutTree->root());
-    auto layoutContext = Layout::LayoutContext { *m_layoutState };
-    layoutContext.layout(view().layoutSize());
-
-    // Clean up the render tree state when we don't run RenderView::layout.
-    if (renderView.needsLayout()) {
-        auto contentSize = Layout::BoxGeometry::marginBoxRect(m_layoutState->geometryForBox(*m_layoutState->root().firstChild())).size();
-        renderView.setSize(contentSize);
-        renderView.repaintViewRectangle({ 0, 0, contentSize.width(), contentSize.height() });
-
-        for (auto& descendant : descendantsOfType<RenderObject>(renderView))
-            descendant.clearNeedsLayout();
-        renderView.clearNeedsLayout();
-    }
-#if ASSERT_ENABLED
-    Layout::LayoutContext::verifyAndOutputMismatchingLayoutTree(*m_layoutState, renderView);
-#endif
-}
-
 static bool isObjectAncestorContainerOf(RenderElement& ancestor, RenderElement& descendant)
 {
     for (auto* renderer = &descendant; renderer; renderer = renderer->container()) {
@@ -266,7 +234,6 @@ void LocalFrameViewLayoutContext::performLayout()
         RenderTreeNeedsLayoutChecker checker(*renderView());
 #endif
         layoutRoot->layout();
-        layoutUsingFormattingContext();
         ++m_layoutCount;
 #if ENABLE(TEXT_AUTOSIZING)
         applyTextSizingIfNeeded(*layoutRoot.get());

Source/WebCore/page/LocalFrameViewLayoutContext.h

@@ -165,7 +165,6 @@ class LocalFrameViewLayoutContext {
     // These functions may only be accessed by LayoutStateMaintainer or LayoutStateDisabler.
     void disablePaintOffsetCache() { m_paintOffsetCacheDisableCount++; }
     void enablePaintOffsetCache() { ASSERT(m_paintOffsetCacheDisableCount > 0); m_paintOffsetCacheDisableCount--; }
-    void layoutUsingFormattingContext();
 
     LocalFrame& frame() const;
     LocalFrameView& view() const;