LibHTML: Start fleshing out a StyleResolver class.

This will be responsible for matching selectors and creating LayoutStyle
objects for the document and its elements.

LibHTML/CSS/StyleResolver.cpp

@@ -0,0 +1,23 @@
+#include <LibHTML/CSS/StyleResolver.h>
+#include <LibHTML/CSS/StyleSheet.h>
+
+StyleResolver::StyleResolver(Document& document)
+    : m_document(document)
+{
+}
+
+StyleResolver::~StyleResolver()
+{
+}
+
+OwnPtr<LayoutStyle> StyleResolver::resolve_document_style(const Document& document)
+{
+    UNUSED_PARAM(document);
+    return nullptr;
+}
+
+OwnPtr<LayoutStyle> StyleResolver::resolve_element_style(const Element& element)
+{
+    UNUSED_PARAM(element);
+    return nullptr;
+}

LibHTML/CSS/StyleResolver.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <AK/NonnullRefPtrVector.h>
+#include <LibHTML/Layout/LayoutStyle.h>
+
+class Document;
+class Element;
+class StyleSheet;
+
+class StyleResolver {
+public:
+    explicit StyleResolver(Document&);
+    ~StyleResolver();
+
+    Document& document() { return m_document; }
+    const Document& document() const { return m_document; }
+
+    void add_sheet(const StyleSheet& sheet) { m_sheets.append(sheet); }
+
+    OwnPtr<LayoutStyle> resolve_element_style(const Element&);
+    OwnPtr<LayoutStyle> resolve_document_style(const Document&);
+
+private:
+    Document& m_document;
+
+    NonnullRefPtrVector<StyleSheet> m_sheets;
+};

LibHTML/Makefile.shared

@@ -10,6 +10,7 @@ LIBHTML_OBJS = \
     CSS/StyleDeclaration.o \
     CSS/StyleValue.o \
     CSS/StyledNode.o \
+    CSS/StyleResolver.o \
     CSS/DefaultStyleSheetSource.o \
     Parser/HTMLParser.o \
     Parser/CSSParser.o \

LibHTML/test.cpp

@@ -2,6 +2,7 @@
 #include <LibHTML/Dump.h>
 #include <LibHTML/Frame.h>
 #include <LibHTML/Parser/CSSParser.h>
+#include <LibHTML/CSS/StyleResolver.h>
 #include <LibHTML/Parser/HTMLParser.h>
 #include <stdio.h>
 
@@ -23,6 +24,11 @@ int main(int argc, char** argv)
     auto doc = parse_html(html);
     dump_tree(doc);
 
+    StyleResolver resolver(*doc);
+    resolver.add_sheet(*sheet);
+
+    auto doc_style = resolver.resolve_document_style(*doc);
+
     doc->build_layout_tree();
     ASSERT(doc->layout_node());