Add EventHandlerRegistry

Source/core/frame/LocalFrame.cpp

Index: Source/core/frame/LocalFrame.cpp
diff --git a/Source/core/frame/LocalFrame.cpp b/Source/core/frame/LocalFrame.cpp
index baf32f31d7ca627fb74b123c8503df22bc52ac09..44ed5c9122ed39593c2ffa168d3b48489376d07b 100644
--- a/Source/core/frame/LocalFrame.cpp
+++ b/Source/core/frame/LocalFrame.cpp
@@ -33,7 +33,7 @@
 #include "RuntimeEnabledFeatures.h"
 #include "bindings/v8/ScriptController.h"
 #include "core/dom/DocumentType.h"
-#include "core/dom/WheelController.h"
+#include "core/dom/EventHandlerRegistry.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/InputMethodController.h"
@@ -466,15 +466,17 @@ void LocalFrame::deviceOrPageScaleFactorChanged()
 
 void LocalFrame::notifyChromeClientWheelEventHandlerCountChanged() const
 {
+    // TODO(skyostil): No-one is using this information, so remove this code.
     // Ensure that this method is being called on the main frame of the page.
     ASSERT(isMainFrame());
 
-    unsigned count = 0;
-    for (const LocalFrame* frame = this; frame; frame = frame->tree().traverseNext()) {
-        if (frame->document())
-            count += WheelController::from(*frame->document())->wheelEventHandlerCount();
+    EventHandlerRegistry* registry = EventHandlerRegistry::from(*document());
+    unsigned count = registry->externalEventHandlerCount(EventHandlerRegistry::WheelEvent);
+    const EventTargetSet* targets = registry->eventHandlerTargets(EventHandlerRegistry::WheelEvent);
+    if (targets) {
+        for (EventTargetSet::const_iterator iter = targets->begin(); iter != targets->end(); ++iter)
+            count += iter->value;
     }
-
     m_host->chrome().client().numWheelEventHandlersChanged(count);
 }