Implement HTMLMediaElement::srcObject.

Source/core/html/MediaProvider.h

Index: Source/core/html/MediaProvider.h
diff --git a/Source/core/dom/custom/CustomElementAsyncImportMicrotaskQueue.cpp b/Source/core/html/MediaProvider.h
similarity index 67%
copy from Source/core/dom/custom/CustomElementAsyncImportMicrotaskQueue.cpp
copy to Source/core/html/MediaProvider.h
index d5e946c4b0c7c7c94903f766a0981b4648e30b69..02efeda73a0412b7268c7c511d73e36d4f07d4af 100644
--- a/Source/core/dom/custom/CustomElementAsyncImportMicrotaskQueue.cpp
+++ b/Source/core/html/MediaProvider.h
@@ -28,28 +28,32 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "config.h"
-#include "core/dom/custom/CustomElementAsyncImportMicrotaskQueue.h"
+#ifndef MediaProvider_h
+#define MediaProvider_h
 
-#include "core/dom/custom/CustomElementMicrotaskImportStep.h"
+#include "platform/heap/Handle.h"
+#include "wtf/Functional.h"
 
 namespace blink {
 
-void CustomElementAsyncImportMicrotaskQueue::enqueue(PassOwnPtrWillBeRawPtr<CustomElementMicrotaskStep> step)
-{
-    m_queue.append(step);
-}
+class EventTarget;
+class MediaProvider;
+class ScriptValue;
 
-void CustomElementAsyncImportMicrotaskQueue::doDispatch()
-{
-    WillBeHeapVector<OwnPtrWillBeMember<CustomElementMicrotaskStep> > remaining;
+class MediaProvider : public WillBeGarbageCollectedMixin {
+public:
+    // Converter must be a static function and is used for converting between a ScriptValue and a MediaProvider instance.
+    // If the ScriptValue can not be converted to a MediaProvider, the function must return null.
+    typedef Function<MediaProvider*(const ScriptValue&)> Converter;
+    static MediaProvider* convert(const ScriptValue&);
 
-    for (unsigned i = 0; i < m_queue.size(); ++i) {
-        if (CustomElementMicrotaskStep::Processing == m_queue[i]->process())
-            remaining.append(m_queue[i].release());
-    }
+    MediaProvider(const String& interfaceName, const Converter&);
+    virtual ~MediaProvider() { };
 
-    m_queue.swap(remaining);
-}
+    virtual EventTarget* eventTarget() = 0;
+    virtual const String& getObjectUrl() = 0;
+};
 
 } // namespace blink
+
+#endif