LibWeb: Make DOM::Node::set_needs_style_update() schedule the update

After you mark a node as needing new style, there's no situation in
which we don't want a style update to happen, so just take care of
scheduling it automatically.

Libraries/LibWeb/DOM/Element.cpp

@@ -267,7 +267,6 @@ void Element::set_inner_html(StringView markup)
     }
 
     set_needs_style_update(true);
-    document().schedule_style_update();
     document().invalidate_layout();
 }
 

Libraries/LibWeb/DOM/Node.cpp

@@ -102,7 +102,6 @@ void Node::set_text_content(const String& content)
     }
 
     set_needs_style_update(true);
-    document().schedule_style_update();
     document().invalidate_layout();
 }
 
@@ -250,4 +249,13 @@ EventTarget* Node::get_parent(const Event&)
     return parent();
 }
 
+void Node::set_needs_style_update(bool value)
+{
+    if (m_needs_style_update == value)
+        return;
+    m_needs_style_update = value;
+    if (m_needs_style_update)
+        document().schedule_style_update();
+}
+
 }

Libraries/LibWeb/DOM/Node.h

@@ -138,7 +138,7 @@ public:
     virtual bool is_child_allowed(const Node&) const { return true; }
 
     bool needs_style_update() const { return m_needs_style_update; }
-    void set_needs_style_update(bool value) { m_needs_style_update = value; }
+    void set_needs_style_update(bool);
 
     void invalidate_style();
 

Libraries/LibWeb/HTML/HTMLElement.cpp

@@ -105,7 +105,6 @@ void HTMLElement::set_inner_text(StringView text)
     append_child(document().create_text_node(text));
 
     set_needs_style_update(true);
-    document().schedule_style_update();
     document().invalidate_layout();
 }