LibWeb: Ensure inline CSS loaded from HTML is ElementInline

This commit changes inline CSS loaded from style attributes of HTML
elements to be loaded as CSS::ElementInlineCSSStyleDeclaration instead
of CSS::CSSStyleDeclaration, fixing a crash when the style of that
element is changed from JavaScript.

Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp

@@ -32,6 +32,12 @@ ElementInlineCSSStyleDeclaration::ElementInlineCSSStyleDeclaration(DOM::Element&
 {
 }
 
+ElementInlineCSSStyleDeclaration::ElementInlineCSSStyleDeclaration(DOM::Element& element, CSSStyleDeclaration& declaration)
+ : CSSStyleDeclaration(move(declaration.m_properties), move(declaration.m_custom_properties))
+ , m_element(element.make_weak_ptr<DOM::Element>())
+{
+}
+
 ElementInlineCSSStyleDeclaration::~ElementInlineCSSStyleDeclaration()
 {
 }

Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.h

@@ -44,6 +44,7 @@ class CSSStyleDeclaration
  explicit CSSStyleDeclaration(Vector<StyleProperty>&&, HashMap<String, StyleProperty>&&);
 
 private:
+ friend class ElementInlineCSSStyleDeclaration;
  friend class Bindings::CSSStyleDeclarationWrapper;
 
  Vector<StyleProperty> m_properties;
@@ -53,13 +54,15 @@ class CSSStyleDeclaration
 class ElementInlineCSSStyleDeclaration final : public CSSStyleDeclaration {
 public:
  static NonnullRefPtr<ElementInlineCSSStyleDeclaration> create(DOM::Element& element) { return adopt_ref(*new ElementInlineCSSStyleDeclaration(element)); }
+ static NonnullRefPtr<ElementInlineCSSStyleDeclaration> create_and_take_properties_from(DOM::Element& element, CSSStyleDeclaration& declaration) { return adopt_ref(*new ElementInlineCSSStyleDeclaration(element, declaration)); }
  virtual ~ElementInlineCSSStyleDeclaration() override;
 
  DOM::Element* element() { return m_element.ptr(); }
  const DOM::Element* element() const { return m_element.ptr(); }
 
 private:
  explicit ElementInlineCSSStyleDeclaration(DOM::Element&);
+ explicit ElementInlineCSSStyleDeclaration(DOM::Element&, CSSStyleDeclaration&);
 
  WeakPtr<DOM::Element> m_element;
 };

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -158,8 +158,11 @@ void Element::parse_attribute(const FlyString& name, const String& value)
  m_classes.unchecked_append(new_class);
  }
  } else if (name == HTML::AttributeNames::style) {
- m_inline_style = parse_css_declaration(CSS::ParsingContext(document()), value);
- set_needs_style_update(true);
+ auto parsed_style = parse_css_declaration(CSS::ParsingContext(document()), value);
+ if (!parsed_style.is_null()) {
+ m_inline_style = CSS::ElementInlineCSSStyleDeclaration::create_and_take_properties_from(*this, parsed_style.release_nonnull());
+ set_needs_style_update(true);
+ }
  }
 }