LibWeb: Rename Layout::InitialContainingBlock to Layout::Viewport

The name "initial containing block" was wrong for this, as it doesn't
correspond to the HTML element, and that's specifically what it's
supposed to do! :^)

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -326,7 +326,7 @@ set(SOURCES
     Layout/FrameBox.cpp
     Layout/GridFormattingContext.cpp
     Layout/ImageBox.cpp
-    Layout/InitialContainingBlock.cpp
+    Layout/Viewport.cpp
     Layout/InlineFormattingContext.cpp
     Layout/InlineLevelIterator.cpp
     Layout/InlineNode.cpp

Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp

@@ -14,7 +14,7 @@
 #include <LibWeb/CSS/StyleComputer.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/Element.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/PaintableBox.h>
 #include <LibWeb/Painting/StackingContext.h>
 
@@ -493,9 +493,9 @@ RefPtr<StyleValue const> ResolvedCSSStyleDeclaration::style_value_for_property(L
             return IdentifierStyleValue::create(ValueID::None);
 
         // The transform matrix is held by the StackingContext, so we need to make sure we have one first.
-        auto* initial_containing_block = layout_node.document().layout_node();
-        VERIFY(initial_containing_block);
-        const_cast<Layout::InitialContainingBlock&>(*initial_containing_block).build_stacking_context_tree_if_needed();
+        auto const* viewport = layout_node.document().layout_node();
+        VERIFY(viewport);
+        const_cast<Layout::Viewport&>(*viewport).build_stacking_context_tree_if_needed();
 
         VERIFY(layout_node.paintable());
         auto const& paintable_box = verify_cast<Painting::PaintableBox const>(layout_node.paintable());

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -65,8 +65,8 @@
 #include <LibWeb/HighResolutionTime/TimeOrigin.h>
 #include <LibWeb/Infra/Strings.h>
 #include <LibWeb/Layout/BlockFormattingContext.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/TreeBuilder.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Namespace.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Platform/Timer.h>
@@ -849,7 +849,7 @@ void Document::update_layout()
     if (!m_layout_root) {
         m_next_layout_node_serial_id = 0;
         Layout::TreeBuilder tree_builder;
-        m_layout_root = verify_cast<Layout::InitialContainingBlock>(*tree_builder.build(*this));
+        m_layout_root = verify_cast<Layout::Viewport>(*tree_builder.build(*this));
     }
 
     Layout::LayoutState layout_state;
@@ -858,10 +858,10 @@ void Document::update_layout()
     {
         Layout::BlockFormattingContext root_formatting_context(layout_state, *m_layout_root, nullptr);
 
-        auto& icb = static_cast<Layout::InitialContainingBlock&>(*m_layout_root);
-        auto& icb_state = layout_state.get_mutable(icb);
-        icb_state.set_content_width(viewport_rect.width());
-        icb_state.set_content_height(viewport_rect.height());
+        auto& viewport = static_cast<Layout::Viewport&>(*m_layout_root);
+        auto& viewport_state = layout_state.get_mutable(viewport);
+        viewport_state.set_content_width(viewport_rect.width());
+        viewport_state.set_content_height(viewport_rect.height());
 
         root_formatting_context.run(
             *m_layout_root,
@@ -947,14 +947,14 @@ void Document::set_visited_link_color(Color color)
     m_visited_link_color = color;
 }
 
-Layout::InitialContainingBlock const* Document::layout_node() const
+Layout::Viewport const* Document::layout_node() const
 {
-    return static_cast<Layout::InitialContainingBlock const*>(Node::layout_node());
+    return static_cast<Layout::Viewport const*>(Node::layout_node());
 }
 
-Layout::InitialContainingBlock* Document::layout_node()
+Layout::Viewport* Document::layout_node()
 {
-    return static_cast<Layout::InitialContainingBlock*>(Node::layout_node());
+    return static_cast<Layout::Viewport*>(Node::layout_node());
 }
 
 void Document::set_inspected_node(Node* node)

Userland/Libraries/LibWeb/DOM/Document.h

@@ -196,8 +196,8 @@ public:
 
     virtual bool is_child_allowed(Node const&) const override;
 
-    Layout::InitialContainingBlock const* layout_node() const;
-    Layout::InitialContainingBlock* layout_node();
+    Layout::Viewport const* layout_node() const;
+    Layout::Viewport* layout_node();
 
     void schedule_style_update();
     void schedule_layout_update();
@@ -477,7 +477,7 @@ private:
 
     JS::GCPtr<HTML::Window> m_window;
 
-    JS::GCPtr<Layout::InitialContainingBlock> m_layout_root;
+    JS::GCPtr<Layout::Viewport> m_layout_root;
 
     Optional<Color> m_link_color;
     Optional<Color> m_active_link_color;

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -38,7 +38,6 @@
 #include <LibWeb/Infra/CharacterTypes.h>
 #include <LibWeb/Infra/Strings.h>
 #include <LibWeb/Layout/BlockContainer.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/InlineNode.h>
 #include <LibWeb/Layout/ListItemBox.h>
 #include <LibWeb/Layout/TableBox.h>
@@ -46,6 +45,7 @@
 #include <LibWeb/Layout/TableRowBox.h>
 #include <LibWeb/Layout/TableRowGroupBox.h>
 #include <LibWeb/Layout/TreeBuilder.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Namespace.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Painting/PaintableBox.h>

Userland/Libraries/LibWeb/DOM/Node.cpp

@@ -35,9 +35,9 @@
 #include <LibWeb/HTML/Origin.h>
 #include <LibWeb/HTML/Parser/HTMLParser.h>
 #include <LibWeb/Infra/CharacterTypes.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/Node.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 
 namespace Web::DOM {
 

Userland/Libraries/LibWeb/DOM/Range.cpp

@@ -17,7 +17,7 @@
 #include <LibWeb/DOM/Text.h>
 #include <LibWeb/Geometry/DOMRect.h>
 #include <LibWeb/HTML/Window.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 
 namespace Web::DOM {
 

Userland/Libraries/LibWeb/Forward.h

@@ -447,7 +447,7 @@ class CheckBox;
 class FlexFormattingContext;
 class FormattingContext;
 struct LayoutState;
-class InitialContainingBlock;
+class Viewport;
 class InlineFormattingContext;
 class Label;
 class LabelableNode;

Userland/Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -24,8 +24,8 @@
 #include <LibWeb/HighResolutionTime/TimeOrigin.h>
 #include <LibWeb/Infra/Strings.h>
 #include <LibWeb/Layout/BreakNode.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/URL/URL.h>
 

Userland/Libraries/LibWeb/HTML/Window.cpp

@@ -53,7 +53,7 @@
 #include <LibWeb/HighResolutionTime/TimeOrigin.h>
 #include <LibWeb/Infra/Base64.h>
 #include <LibWeb/Infra/CharacterTypes.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/RequestIdleCallback/IdleDeadline.h>
 #include <LibWeb/Selection/Selection.h>

Userland/Libraries/LibWeb/Layout/BlockFormattingContext.cpp

@@ -12,7 +12,6 @@
 #include <LibWeb/Layout/BlockContainer.h>
 #include <LibWeb/Layout/BlockFormattingContext.h>
 #include <LibWeb/Layout/Box.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/InlineFormattingContext.h>
 #include <LibWeb/Layout/LineBuilder.h>
 #include <LibWeb/Layout/ListItemBox.h>
@@ -20,6 +19,7 @@
 #include <LibWeb/Layout/ReplacedBox.h>
 #include <LibWeb/Layout/TableBox.h>
 #include <LibWeb/Layout/TableWrapper.h>
+#include <LibWeb/Layout/Viewport.h>
 
 namespace Web::Layout {
 
@@ -38,11 +38,6 @@ BlockFormattingContext::~BlockFormattingContext()
     }
 }
 
-bool BlockFormattingContext::is_initial() const
-{
-    return is<InitialContainingBlock>(root());
-}
-
 CSSPixels BlockFormattingContext::automatic_content_height() const
 {
     return compute_auto_height_for_block_formatting_context_root(root());
@@ -50,8 +45,8 @@ CSSPixels BlockFormattingContext::automatic_content_height() const
 
 void BlockFormattingContext::run(Box const&, LayoutMode layout_mode, AvailableSpace const& available_space)
 {
-    if (is_initial()) {
-        layout_initial_containing_block(layout_mode, available_space);
+    if (is<Viewport>(root())) {
+        layout_viewport(layout_mode, available_space);
         return;
     }
 
@@ -696,12 +691,12 @@ static void measure_scrollable_overflow(LayoutState const& state, Box const& box
     });
 }
 
-void BlockFormattingContext::layout_initial_containing_block(LayoutMode layout_mode, AvailableSpace const& available_space)
+void BlockFormattingContext::layout_viewport(LayoutMode layout_mode, AvailableSpace const& available_space)
 {
     auto viewport_rect = root().browsing_context().viewport_rect();
 
-    auto& icb = verify_cast<Layout::InitialContainingBlock>(root());
-    auto& icb_state = m_state.get_mutable(icb);
+    auto& viewport = verify_cast<Layout::Viewport>(root());
+    auto& viewport_state = m_state.get_mutable(viewport);
 
     if (root().children_are_inline())
         layout_inline_children(root(), layout_mode, available_space);
@@ -710,11 +705,11 @@ void BlockFormattingContext::layout_initial_containing_block(LayoutMode layout_m
 
     CSSPixels bottom_edge = 0;
     CSSPixels right_edge = 0;
-    measure_scrollable_overflow(m_state, icb, bottom_edge, right_edge);
+    measure_scrollable_overflow(m_state, viewport, bottom_edge, right_edge);
 
     if (bottom_edge >= viewport_rect.height() || right_edge >= viewport_rect.width()) {
         // FIXME: Move overflow data to LayoutState!
-        auto& overflow_data = icb_state.ensure_overflow_data();
+        auto& overflow_data = viewport_state.ensure_overflow_data();
         overflow_data.scrollable_overflow_rect = viewport_rect;
         // NOTE: The edges are *within* the rectangle, so we add 1 to get the width and height.
         overflow_data.scrollable_overflow_rect.set_size(right_edge + 1, bottom_edge + 1);

Userland/Libraries/LibWeb/Layout/BlockFormattingContext.h

@@ -24,8 +24,6 @@ public:
     virtual void run(Box const&, LayoutMode, AvailableSpace const&) override;
     virtual CSSPixels automatic_content_height() const override;
 
-    bool is_initial() const;
-
     auto const& left_side_floats() const { return m_left_floats; }
     auto const& right_side_floats() const { return m_right_floats; }
 
@@ -61,7 +59,7 @@ private:
 
     CSSPixels compute_width_for_table_wrapper(Box const&, AvailableSpace const&);
 
-    void layout_initial_containing_block(LayoutMode, AvailableSpace const&);
+    void layout_viewport(LayoutMode, AvailableSpace const&);
 
     void layout_block_level_children(BlockContainer const&, LayoutMode, AvailableSpace const&);
     void layout_inline_children(BlockContainer const&, LayoutMode, AvailableSpace const&);

Userland/Libraries/LibWeb/Layout/FlexFormattingContext.cpp

@@ -13,9 +13,9 @@
 #include <LibWeb/Layout/BlockFormattingContext.h>
 #include <LibWeb/Layout/Box.h>
 #include <LibWeb/Layout/FlexFormattingContext.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/ReplacedBox.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 
 namespace Web::Layout {
 

Userland/Libraries/LibWeb/Layout/FormattingContext.cpp

@@ -10,13 +10,13 @@
 #include <LibWeb/Layout/FlexFormattingContext.h>
 #include <LibWeb/Layout/FormattingContext.h>
 #include <LibWeb/Layout/GridFormattingContext.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/ReplacedBox.h>
 #include <LibWeb/Layout/SVGFormattingContext.h>
 #include <LibWeb/Layout/SVGSVGBox.h>
 #include <LibWeb/Layout/TableBox.h>
 #include <LibWeb/Layout/TableCellBox.h>
 #include <LibWeb/Layout/TableFormattingContext.h>
+#include <LibWeb/Layout/Viewport.h>
 
 namespace Web::Layout {
 

Userland/Libraries/LibWeb/Layout/FrameBox.cpp

@@ -7,7 +7,7 @@
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/Layout/FrameBox.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/NestedBrowsingContextPaintable.h>
 
 namespace Web::Layout {

Userland/Libraries/LibWeb/Layout/Label.cpp

@@ -7,10 +7,10 @@
 #include <LibGUI/Event.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/Element.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/Label.h>
 #include <LibWeb/Layout/LabelableNode.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/LabelablePaintable.h>
 
 namespace Web::Layout {

Userland/Libraries/LibWeb/Layout/LayoutState.cpp

@@ -26,7 +26,7 @@ LayoutState::UsedValues& LayoutState::get_mutable(NodeWithStyleAndBoxModelMetric
         }
     }
 
-    auto const* containing_block_used_values = box.is_initial_containing_block_box() ? nullptr : &get(*box.containing_block());
+    auto const* containing_block_used_values = box.is_viewport() ? nullptr : &get(*box.containing_block());
 
     used_values_per_layout_node[serial_id] = adopt_own(*new UsedValues);
     used_values_per_layout_node[serial_id]->set_node(const_cast<NodeWithStyleAndBoxModelMetrics&>(box), containing_block_used_values);
@@ -44,7 +44,7 @@ LayoutState::UsedValues const& LayoutState::get(NodeWithStyleAndBoxModelMetrics
             return *ancestor->used_values_per_layout_node[serial_id];
     }
 
-    auto const* containing_block_used_values = box.is_initial_containing_block_box() ? nullptr : &get(*box.containing_block());
+    auto const* containing_block_used_values = box.is_viewport() ? nullptr : &get(*box.containing_block());
 
     const_cast<LayoutState*>(this)->used_values_per_layout_node[serial_id] = adopt_own(*new UsedValues);
     const_cast<LayoutState*>(this)->used_values_per_layout_node[serial_id]->set_node(const_cast<NodeWithStyleAndBoxModelMetrics&>(box), containing_block_used_values);

Userland/Libraries/LibWeb/Layout/LineBoxFragment.cpp

@@ -6,10 +6,10 @@
 
 #include <AK/Utf8View.h>
 #include <LibWeb/DOM/Range.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/LayoutState.h>
 #include <LibWeb/Layout/LineBoxFragment.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <ctype.h>
 
 namespace Web::Layout {

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -11,10 +11,10 @@
 #include <LibWeb/HTML/HTMLHtmlElement.h>
 #include <LibWeb/Layout/BlockContainer.h>
 #include <LibWeb/Layout/FormattingContext.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/Node.h>
 #include <LibWeb/Layout/TableBox.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Platform/FontPlugin.h>
 
 namespace Web::Layout {
@@ -62,7 +62,7 @@ bool Node::can_contain_boxes_with_position_absolute() const
     if (computed_values().position() != CSS::Position::Static)
         return true;
 
-    if (is<InitialContainingBlock>(*this))
+    if (is<Viewport>(*this))
         return true;
 
     // https://w3c.github.io/csswg-drafts/css-transforms-1/#propdef-transform
@@ -163,13 +163,13 @@ HTML::BrowsingContext& Node::browsing_context()
     return *m_browsing_context;
 }
 
-InitialContainingBlock const& Node::root() const
+Viewport const& Node::root() const
 {
     VERIFY(document().layout_node());
     return *document().layout_node();
 }
 
-InitialContainingBlock& Node::root()
+Viewport& Node::root()
 {
     VERIFY(document().layout_node());
     return *document().layout_node();

Userland/Libraries/LibWeb/Layout/Node.h

@@ -62,8 +62,8 @@ public:
     HTML::BrowsingContext const& browsing_context() const;
     HTML::BrowsingContext& browsing_context();
 
-    InitialContainingBlock const& root() const;
-    InitialContainingBlock& root();
+    Viewport const& root() const;
+    Viewport& root();
 
     bool is_root_element() const;
 
@@ -86,7 +86,7 @@ public:
     virtual bool is_block_container() const { return false; }
     virtual bool is_break_node() const { return false; }
     virtual bool is_text_node() const { return false; }
-    virtual bool is_initial_containing_block_box() const { return false; }
+    virtual bool is_viewport() const { return false; }
     virtual bool is_svg_box() const { return false; }
     virtual bool is_svg_geometry_box() const { return false; }
     virtual bool is_label() const { return false; }

Userland/Libraries/LibWeb/Layout/TreeBuilder.cpp

@@ -16,7 +16,6 @@
 #include <LibWeb/Dump.h>
 #include <LibWeb/HTML/HTMLInputElement.h>
 #include <LibWeb/HTML/HTMLProgressElement.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/ListItemBox.h>
 #include <LibWeb/Layout/ListItemMarkerBox.h>
 #include <LibWeb/Layout/Node.h>
@@ -27,6 +26,7 @@
 #include <LibWeb/Layout/TableWrapper.h>
 #include <LibWeb/Layout/TextNode.h>
 #include <LibWeb/Layout/TreeBuilder.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/SVG/SVGForeignObjectElement.h>
 
 namespace Web::Layout {
@@ -219,7 +219,7 @@ ErrorOr<void> TreeBuilder::create_layout_tree(DOM::Node& dom_node, TreeBuilder::
     } else if (is<DOM::Document>(dom_node)) {
         style = style_computer.create_document_style();
         display = style->display();
-        layout_node = document.heap().allocate_without_realm<Layout::InitialContainingBlock>(static_cast<DOM::Document&>(dom_node), *style);
+        layout_node = document.heap().allocate_without_realm<Layout::Viewport>(static_cast<DOM::Document&>(dom_node), *style);
     } else if (is<DOM::Text>(dom_node)) {
         layout_node = document.heap().allocate_without_realm<Layout::TextNode>(document, static_cast<DOM::Text&>(dom_node));
         display = CSS::Display(CSS::Display::Outside::Inline, CSS::Display::Inside::Flow);

Userland/Libraries/LibWeb/Layout/Viewport.cpp

@@ -1,37 +1,37 @@
 /*
- * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibWeb/DOM/Range.h>
 #include <LibWeb/Dump.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/PaintableBox.h>
 #include <LibWeb/Painting/StackingContext.h>
 
 namespace Web::Layout {
 
-InitialContainingBlock::InitialContainingBlock(DOM::Document& document, NonnullRefPtr<CSS::StyleProperties> style)
+Viewport::Viewport(DOM::Document& document, NonnullRefPtr<CSS::StyleProperties> style)
     : BlockContainer(document, &document, move(style))
 {
 }
 
-InitialContainingBlock::~InitialContainingBlock() = default;
+Viewport::~Viewport() = default;
 
-JS::GCPtr<Selection::Selection> InitialContainingBlock::selection() const
+JS::GCPtr<Selection::Selection> Viewport::selection() const
 {
     return const_cast<DOM::Document&>(document()).get_selection();
 }
 
-void InitialContainingBlock::build_stacking_context_tree_if_needed()
+void Viewport::build_stacking_context_tree_if_needed()
 {
     if (paint_box()->stacking_context())
         return;
     build_stacking_context_tree();
 }
 
-void InitialContainingBlock::build_stacking_context_tree()
+void Viewport::build_stacking_context_tree()
 {
     const_cast<Painting::PaintableWithLines*>(paint_box())->set_stacking_context(make<Painting::StackingContext>(*this, nullptr));
 
@@ -52,7 +52,7 @@ void InitialContainingBlock::build_stacking_context_tree()
     const_cast<Painting::PaintableWithLines*>(paint_box())->stacking_context()->sort();
 }
 
-void InitialContainingBlock::paint_all_phases(PaintContext& context)
+void Viewport::paint_all_phases(PaintContext& context)
 {
     build_stacking_context_tree_if_needed();
     context.painter().fill_rect(context.enclosing_device_rect(paint_box()->absolute_rect()).to_type<int>(), document().background_color(context.palette()));
@@ -60,7 +60,7 @@ void InitialContainingBlock::paint_all_phases(PaintContext& context)
     paint_box()->stacking_context()->paint(context);
 }
 
-void InitialContainingBlock::recompute_selection_states()
+void Viewport::recompute_selection_states()
 {
     // 1. Start by resetting the selection state of all layout nodes to None.
     for_each_in_inclusive_subtree([&](auto& layout_node) {

Userland/Libraries/LibWeb/Layout/Viewport.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2023, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -12,12 +12,12 @@
 
 namespace Web::Layout {
 
-class InitialContainingBlock final : public BlockContainer {
-    JS_CELL(InitialContainingBlock, BlockContainer);
+class Viewport final : public BlockContainer {
+    JS_CELL(Viewport, BlockContainer);
 
 public:
-    explicit InitialContainingBlock(DOM::Document&, NonnullRefPtr<CSS::StyleProperties>);
-    virtual ~InitialContainingBlock() override;
+    explicit Viewport(DOM::Document&, NonnullRefPtr<CSS::StyleProperties>);
+    virtual ~Viewport() override;
 
     const DOM::Document& dom_node() const { return static_cast<const DOM::Document&>(*Node::dom_node()); }
 
@@ -30,10 +30,10 @@ public:
 
 private:
     void build_stacking_context_tree();
-    virtual bool is_initial_containing_block_box() const override { return true; }
+    virtual bool is_viewport() const override { return true; }
 };
 
 template<>
-inline bool Node::fast_is<InitialContainingBlock>() const { return is_initial_containing_block_box(); }
+inline bool Node::fast_is<Viewport>() const { return is_viewport(); }
 
 }

Userland/Libraries/LibWeb/Page/EditEventHandler.cpp

@@ -11,7 +11,7 @@
 #include <LibWeb/DOM/Range.h>
 #include <LibWeb/DOM/Text.h>
 #include <LibWeb/HTML/BrowsingContext.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Page/EditEventHandler.h>
 
 namespace Web {

Userland/Libraries/LibWeb/Page/EventHandler.cpp

@@ -13,7 +13,7 @@
 #include <LibWeb/HTML/HTMLAnchorElement.h>
 #include <LibWeb/HTML/HTMLIFrameElement.h>
 #include <LibWeb/HTML/HTMLImageElement.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Page/EventHandler.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Painting/PaintableBox.h>
@@ -119,14 +119,14 @@ EventHandler::EventHandler(Badge<HTML::BrowsingContext>, HTML::BrowsingContext&
 
 EventHandler::~EventHandler() = default;
 
-Layout::InitialContainingBlock const* EventHandler::layout_root() const
+Layout::Viewport const* EventHandler::layout_root() const
 {
     if (!m_browsing_context.active_document())
         return nullptr;
     return m_browsing_context.active_document()->layout_node();
 }
 
-Layout::InitialContainingBlock* EventHandler::layout_root()
+Layout::Viewport* EventHandler::layout_root()
 {
     if (!m_browsing_context.active_document())
         return nullptr;

Userland/Libraries/LibWeb/Page/EventHandler.h

@@ -44,8 +44,8 @@ private:
     CSSPixelPoint compute_mouse_event_client_offset(CSSPixelPoint event_page_position) const;
     CSSPixelPoint compute_mouse_event_page_offset(CSSPixelPoint event_client_offset) const;
 
-    Layout::InitialContainingBlock* layout_root();
-    Layout::InitialContainingBlock const* layout_root() const;
+    Layout::Viewport* layout_root();
+    Layout::Viewport const* layout_root() const;
 
     Painting::PaintableBox* paint_root();
     Painting::PaintableBox const* paint_root() const;

Userland/Libraries/LibWeb/Painting/BackgroundPainting.cpp

@@ -8,8 +8,8 @@
 
 #include <LibGfx/AntiAliasingPainter.h>
 #include <LibGfx/Painter.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/Node.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/BackgroundPainting.h>
 #include <LibWeb/Painting/BorderRadiusCornerClipper.h>
 #include <LibWeb/Painting/GradientPainting.h>

Userland/Libraries/LibWeb/Painting/NestedBrowsingContextPaintable.cpp

@@ -7,7 +7,7 @@
 #include <AK/Debug.h>
 #include <LibWeb/HTML/BrowsingContextContainer.h>
 #include <LibWeb/Layout/FrameBox.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/BorderRadiusCornerClipper.h>
 #include <LibWeb/Painting/NestedBrowsingContextPaintable.h>
 
@@ -54,7 +54,7 @@ void NestedBrowsingContextPaintable::paint(PaintContext& context, PaintPhase pha
         context.painter().translate(absolute_rect.x().value(), absolute_rect.y().value());
 
         context.set_device_viewport_rect({ {}, context.enclosing_device_size(layout_box().dom_node().nested_browsing_context()->size()) });
-        const_cast<Layout::InitialContainingBlock*>(hosted_layout_tree)->paint_all_phases(context);
+        const_cast<Layout::Viewport*>(hosted_layout_tree)->paint_all_phases(context);
 
         context.set_device_viewport_rect(old_viewport_rect);
         context.painter().restore();

Userland/Libraries/LibWeb/Painting/PaintableBox.cpp

@@ -11,7 +11,7 @@
 #include <LibWeb/FontCache.h>
 #include <LibWeb/HTML/HTMLHtmlElement.h>
 #include <LibWeb/Layout/BlockContainer.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/BackgroundPainting.h>
 #include <LibWeb/Painting/FilterPainting.h>
 #include <LibWeb/Painting/PaintableBox.h>
@@ -141,7 +141,7 @@ Painting::StackingContext* PaintableBox::enclosing_stacking_context()
         if (auto* ancestor_paint_box = ancestor_box.paint_box(); ancestor_paint_box && ancestor_paint_box->stacking_context())
             return const_cast<StackingContext*>(ancestor_paint_box->stacking_context());
     }
-    // We should always reach the Layout::InitialContainingBlock stacking context.
+    // We should always reach the Layout::Viewport stacking context.
     VERIFY_NOT_REACHED();
 }
 
@@ -686,8 +686,8 @@ Optional<HitTestResult> PaintableBox::hit_test(CSSPixelPoint position, HitTestTy
     if (!is_visible())
         return {};
 
-    if (layout_box().is_initial_containing_block_box()) {
-        const_cast<Layout::InitialContainingBlock&>(static_cast<Layout::InitialContainingBlock const&>(layout_box())).build_stacking_context_tree_if_needed();
+    if (layout_box().is_viewport()) {
+        const_cast<Layout::Viewport&>(static_cast<Layout::Viewport const&>(layout_box())).build_stacking_context_tree_if_needed();
         return stacking_context()->hit_test(position, type);
     }
 

Userland/Libraries/LibWeb/Painting/StackingContext.cpp

@@ -14,8 +14,8 @@
 #include <LibGfx/Painter.h>
 #include <LibGfx/Rect.h>
 #include <LibWeb/Layout/Box.h>
-#include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/ReplacedBox.h>
+#include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Painting/PaintableBox.h>
 #include <LibWeb/Painting/StackingContext.h>