LibWeb: Move Attribute to its own header file

This will allow us to use it without including Element.h

Libraries/LibWeb/DOM/Attribute.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/FlyString.h>
+
+namespace Web {
+
+class Attribute {
+public:
+    Attribute(const FlyString& name, const String& value)
+        : m_name(name)
+        , m_value(value)
+    {
+    }
+
+    const FlyString& name() const { return m_name; }
+    const String& value() const { return m_value; }
+
+    void set_value(const String& value) { m_value = value; }
+
+private:
+    FlyString m_name;
+    String m_value;
+};
+
+}

Libraries/LibWeb/DOM/Element.h

@@ -28,6 +28,7 @@
 
 #include <AK/FlyString.h>
 #include <AK/String.h>
+#include <LibWeb/DOM/Attribute.h>
 #include <LibWeb/DOM/ParentNode.h>
 #include <LibWeb/Layout/LayoutNode.h>
 
@@ -35,24 +36,6 @@ namespace Web {
 
 class LayoutNodeWithStyle;
 
-class Attribute {
-public:
-    Attribute(const FlyString& name, const String& value)
-        : m_name(name)
-        , m_value(value)
-    {
-    }
-
-    const FlyString& name() const { return m_name; }
-    const String& value() const { return m_value; }
-
-    void set_value(const String& value) { m_value = value; }
-
-private:
-    FlyString m_name;
-    String m_value;
-};
-
 class Element : public ParentNode {
 public:
     using WrapperType = Bindings::ElementWrapper;
@@ -77,7 +60,7 @@ public:
 
     bool has_class(const StringView&) const;
 
-    virtual void apply_presentational_hints(StyleProperties&) const {}
+    virtual void apply_presentational_hints(StyleProperties&) const { }
     virtual void parse_attribute(const FlyString& name, const String& value);
 
     void recompute_style();