Add EventHandlerRegistry

Source/core/testing/Internals.cpp

Index: Source/core/testing/Internals.cpp
diff --git a/Source/core/testing/Internals.cpp b/Source/core/testing/Internals.cpp
index 5ba85e137c74ce44d20b5837e47c42632839f99e..4ac0c8ccfd29d09e7d1b46c9c6d46cd23efd2c88 100644
--- a/Source/core/testing/Internals.cpp
+++ b/Source/core/testing/Internals.cpp
@@ -62,6 +62,7 @@
 #include "core/dom/NodeRenderStyle.h"
 #include "core/dom/PseudoElement.h"
 #include "core/dom/Range.h"
+#include "core/dom/ScrollEventHandlerController.h"
 #include "core/dom/StaticNodeList.h"
 #include "core/dom/TreeScope.h"
 #include "core/dom/ViewportDescription.h"
@@ -1287,6 +1288,16 @@ unsigned Internals::wheelEventHandlerCount(Document* document, ExceptionState& e
     return WheelController::from(*document)->wheelEventHandlerCount();
 }
 
+unsigned Internals::scrollEventHandlerCount(Document* document, ExceptionState& exceptionState)
+{
+    if (!document) {
+        exceptionState.throwDOMException(InvalidAccessError, "No context document is available.");
+        return 0;
+    }
+
+    return ScrollEventHandlerController::from(*document)->scrollEventHandlerCount();
+}
+
 unsigned Internals::touchEventHandlerCount(Document* document, ExceptionState& exceptionState)
 {
     if (!document) {