Add picture related attributes to Source

Source/core/html/HTMLSourceElement.cpp

Index: Source/core/html/HTMLSourceElement.cpp
diff --git a/Source/core/html/HTMLSourceElement.cpp b/Source/core/html/HTMLSourceElement.cpp
index 6c613b47a50fc021c7edb8c8a910331f38f80fc6..8d0b6609b9ee16e0527d6a9fd7b11010eb5c08dd 100644
--- a/Source/core/html/HTMLSourceElement.cpp
+++ b/Source/core/html/HTMLSourceElement.cpp
@@ -89,6 +89,21 @@ const AtomicString& HTMLSourceElement::type() const
     return getAttribute(typeAttr);
 }
 
+const AtomicString& HTMLSourceElement::media() const
+{
+    return getAttribute(mediaAttr);
+}
+
+const AtomicString& HTMLSourceElement::srcset() const
+{
+    return getAttribute(srcsetAttr);
+}
+
+const AtomicString& HTMLSourceElement::sizes() const
+{
+    return getAttribute(sizesAttr);
+}
+
 void HTMLSourceElement::setType(const AtomicString& type)
 {
     setAttribute(typeAttr, type);