Notify <picture> elements when a media query (potentially) changes

Source/core/html/HTMLSourceElement.h

Index: Source/core/html/HTMLSourceElement.h
diff --git a/Source/core/html/HTMLSourceElement.h b/Source/core/html/HTMLSourceElement.h
index 339c12a99af11064554671698340eb12d8e6fb4a..02f4a0ac551691054ca88d980180581df3b30986 100644
--- a/Source/core/html/HTMLSourceElement.h
+++ b/Source/core/html/HTMLSourceElement.h
@@ -26,6 +26,7 @@
 #ifndef HTMLSourceElement_h
 #define HTMLSourceElement_h
 
+#include "core/css/MediaQueryListListener.h"
 #include "core/html/HTMLElement.h"
 #include "platform/Timer.h"
 
@@ -36,6 +37,8 @@ typedef EventSender<HTMLSourceElement> SourceEventSender;
 
 class HTMLSourceElement FINAL : public HTMLElement {
 public:
+    class Listener;
+
     DECLARE_NODE_FACTORY(HTMLSourceElement);
     virtual ~HTMLSourceElement();
 
@@ -48,6 +51,8 @@ public:
 
     void dispatchPendingEvent(SourceEventSender*);
 
+    bool mediaQueryMatches() const;
+
 private:
     explicit HTMLSourceElement(Document&);
 
@@ -55,6 +60,12 @@ private:
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
+
+    void notifyMediaQueryChanged();
+    virtual void trace(Visitor*) OVERRIDE;
+
+    RefPtrWillBeMember<MediaQueryList> m_mediaQueryList;
+    RefPtrWillBeMember<Listener> m_listener;
 };
 
 } // namespace WebCore