Migrate wheel events to EventHandlerRegistry

Source/core/frame/EventHandlerRegistry.cpp

Index: Source/core/frame/EventHandlerRegistry.cpp
diff --git a/Source/core/frame/EventHandlerRegistry.cpp b/Source/core/frame/EventHandlerRegistry.cpp
index 5161cf92e82630ebc6e88c224c7c0a09c99f858d..0875283575d4a5d3c23c799d0db6ed6abca017cb 100644
--- a/Source/core/frame/EventHandlerRegistry.cpp
+++ b/Source/core/frame/EventHandlerRegistry.cpp
@@ -14,6 +14,15 @@
 
 namespace WebCore {
 
+EventHandlerRegistry::HandlerState::HandlerState()
+    : externalHandlerCount(0)
+{
+}
+
+EventHandlerRegistry::HandlerState::~HandlerState()
+{
+}
+
 EventHandlerRegistry::EventHandlerRegistry(FrameHost& frameHost)
     : m_frameHost(frameHost)
 {
@@ -28,6 +37,8 @@ bool EventHandlerRegistry::eventTypeToClass(const AtomicString& eventType, Event
 {
     if (eventType == EventTypeNames::scroll) {
         *result = ScrollEvent;
+    } else if (eventType == EventTypeNames::wheel || eventType == EventTypeNames::mousewheel) {
+        *result = WheelEvent;
 #if ASSERT_ENABLED
     } else if (eventType == EventTypeNames::load || eventType == EventTypeNames::mousemove || eventType == EventTypeNames::touchstart) {
         *result = EventsForTesting;
@@ -41,17 +52,34 @@ bool EventHandlerRegistry::eventTypeToClass(const AtomicString& eventType, Event
 const EventTargetSet* EventHandlerRegistry::eventHandlerTargets(EventHandlerClass handlerClass) const
 {
     checkConsistency();
-    return &m_targets[handlerClass];
+    return &m_handlers[handlerClass].targets;
+}
+
+unsigned EventHandlerRegistry::externalEventHandlerCount(EventHandlerClass handlerClass) const
+{
+    return m_handlers[handlerClass].externalHandlerCount;
 }
 
 bool EventHandlerRegistry::hasEventHandlers(EventHandlerClass handlerClass) const
 {
-    return m_targets[handlerClass].size();
+    const HandlerState& state = m_handlers[handlerClass];
+    return state.targets.size() || state.externalHandlerCount;
+}
+
+void EventHandlerRegistry::updateExternalHandlerCount(ChangeOperation op, EventHandlerClass handlerClass)
+{
+    if (op == Add) {
+        m_handlers[handlerClass].externalHandlerCount++;
+    } else {
+        ASSERT(op == Remove);
+        ASSERT(m_handlers[handlerClass].externalHandlerCount > 0);
+        m_handlers[handlerClass].externalHandlerCount--;
+    }
 }
 
 bool EventHandlerRegistry::updateEventHandlerTargets(ChangeOperation op, EventHandlerClass handlerClass, EventTarget* target)
 {
-    EventTargetSet* targets = &m_targets[handlerClass];
+    EventTargetSet* targets = &m_handlers[handlerClass].targets;
     if (op == Add) {
         if (!targets->add(target).isNewEntry) {
             // Just incremented refcount, no real change.
@@ -78,7 +106,11 @@ bool EventHandlerRegistry::updateEventHandlerTargets(ChangeOperation op, EventHa
 void EventHandlerRegistry::updateEventHandlerInternal(ChangeOperation op, EventHandlerClass handlerClass, EventTarget* target)
 {
     bool hadHandlers = hasEventHandlers(handlerClass);
-    updateEventHandlerTargets(op, handlerClass, target);
+    if (target) {
+        updateEventHandlerTargets(op, handlerClass, target);
+    } else {
+        updateExternalHandlerCount(op, handlerClass);
+    }
     bool hasHandlers = hasEventHandlers(handlerClass);
 
     if (hadHandlers != hasHandlers) {
@@ -95,6 +127,16 @@ void EventHandlerRegistry::updateEventHandlerOfType(ChangeOperation op, const At
     updateEventHandlerInternal(op, handlerClass, target);
 }
 
+void EventHandlerRegistry::didAddExternalEventHandler(const AtomicString& eventType)
+{
+    updateEventHandlerOfType(Add, eventType, 0);
+}
+
+void EventHandlerRegistry::didRemoveExternalEventHandler(const AtomicString& eventType)
+{
+    updateEventHandlerOfType(Remove, eventType, 0);
+}
+
 void EventHandlerRegistry::didAddEventHandler(EventTarget& target, const AtomicString& eventType)
 {
     updateEventHandlerOfType(Add, eventType, &target);
@@ -155,12 +197,21 @@ void EventHandlerRegistry::updateAllEventHandlers(ChangeOperation op, EventTarge
 void EventHandlerRegistry::notifyHasHandlersChanged(EventHandlerClass handlerClass, bool hasActiveHandlers)
 {
     ScrollingCoordinator* scrollingCoordinator = m_frameHost.page().scrollingCoordinator();
+    LocalFrame* mainFrame = m_frameHost.page().mainFrame();
 
     switch (handlerClass) {
     case ScrollEvent:
         if (scrollingCoordinator)
             scrollingCoordinator->updateHaveScrollEventHandlers();
         break;
+    case WheelEvent:
+        if (mainFrame) {
+            // TODO(skyostil): This notification is wired up to a black hole, so remove it.
+            mainFrame->notifyChromeClientWheelEventHandlerCountChanged();
+        }
+        if (scrollingCoordinator)
+            scrollingCoordinator->updateHaveWheelEventHandlers();
+        break;
 #if ASSERT_ENABLED
     case EventsForTesting:
         break;
@@ -181,7 +232,7 @@ void EventHandlerRegistry::clearWeakMembers(Visitor* visitor)
     Vector<EventTarget*> deadTargets;
     for (size_t i = 0; i < EventHandlerClassCount; ++i) {
         EventHandlerClass handlerClass = static_cast<EventHandlerClass>(i);
-        const EventTargetSet* targets = &m_targets[handlerClass];
+        const EventTargetSet* targets = &m_handlers[handlerClass].targets;
         for (EventTargetSet::const_iterator it = targets->begin(); it != targets->end(); ++it) {
             Node* node = it->key->toNode();
             DOMWindow* window = it->key->toDOMWindow();
@@ -202,7 +253,7 @@ void EventHandlerRegistry::documentDetached(Document& document)
     for (size_t handlerClassIndex = 0; handlerClassIndex < EventHandlerClassCount; ++handlerClassIndex) {
         EventHandlerClass handlerClass = static_cast<EventHandlerClass>(handlerClassIndex);
         Vector<EventTarget*> targetsToRemove;
-        const EventTargetSet* targets = &m_targets[handlerClass];
+        const EventTargetSet* targets = &m_handlers[handlerClass].targets;
         for (EventTargetSet::const_iterator iter = targets->begin(); iter != targets->end(); ++iter) {
             if (Node* node = iter->key->toNode()) {
                 for (Document* doc = &node->document(); doc; doc = doc->ownerElement() ? &doc->ownerElement()->document() : 0) {
@@ -228,7 +279,7 @@ void EventHandlerRegistry::checkConsistency() const
 #if ASSERT_ENABLED
     for (size_t i = 0; i < EventHandlerClassCount; ++i) {
         EventHandlerClass handlerClass = static_cast<EventHandlerClass>(i);
-        const EventTargetSet* targets = &m_targets[handlerClass];
+        const EventTargetSet* targets = &m_handlers[handlerClass].targets;
         for (EventTargetSet::const_iterator iter = targets->begin(); iter != targets->end(); ++iter) {
             if (Node* node = iter->key->toNode()) {
                 // See the comment for |documentDetached| if either of these assertions fails.