diff --git a/WebCore/ChangeLog b/WebCore/ChangeLog
index 2e5a19e36a82d90c47452c5c67104494954a8f74..daa50ff7b64cacf51c607e6cf430b35f77541c11 100644
--- a/WebCore/ChangeLog
+++ b/WebCore/ChangeLog
@@ -1,3 +1,43 @@
+2009-09-08  Chris Fleizach  <cfleizach@apple.com>
+
+        Reviewed by Darin Adler.
+
+        AX notifications should be an ENUM type instead of strings
+        https://bugs.webkit.org/show_bug.cgi?id=28963
+
+        Moves AX notifications over to an ENUM type instead of
+        using the actual string values that are used on OS X.
+
+        * accessibility/AXObjectCache.cpp:
+        (WebCore::AXObjectCache::postNotification):
+        (WebCore::AXObjectCache::selectedChildrenChanged):
+        * accessibility/AXObjectCache.h:
+        (WebCore::AXObjectCache::):
+        * accessibility/AccessibilityRenderObject.cpp:
+        (WebCore::AccessibilityRenderObject::handleActiveDescendantChanged):
+        * accessibility/chromium/AXObjectCacheChromium.cpp:
+        (WebCore::AXObjectCache::postPlatformNotification):
+        * accessibility/gtk/AXObjectCacheAtk.cpp:
+        (WebCore::AXObjectCache::postPlatformNotification):
+        * accessibility/mac/AXObjectCacheMac.mm:
+        (WebCore::AXObjectCache::postPlatformNotification):
+        * accessibility/win/AXObjectCacheWin.cpp:
+        (WebCore::AXObjectCache::postPlatformNotification):
+        * dom/Document.cpp:
+        (WebCore::Document::implicitClose):
+        * dom/Element.cpp:
+        (WebCore::Element::updateAfterAttributeChanged):
+        * editing/Editor.cpp:
+        (WebCore::Editor::respondToChangedContents):
+        * editing/mac/SelectionControllerMac.mm:
+        (WebCore::SelectionController::notifyAccessibilityForSelectionChange):
+        * html/HTMLInputElement.cpp:
+        (WebCore::HTMLInputElement::setChecked):
+        * page/FrameView.cpp:
+        (WebCore::FrameView::layout):
+        * rendering/RenderTextControl.cpp:
+        (WebCore::RenderTextControl::setInnerTextValue):
+
 2009-09-08  Adam Barth  <abarth@webkit.org>
 
         Reviewed by Eric Seidel.
diff --git a/WebCore/accessibility/AXObjectCache.cpp b/WebCore/accessibility/AXObjectCache.cpp
index f2b274c790d5ae775412afbd7dc9b6f08505b524..55199a32570deb4dac6f15f7ffc247130e0c70af 100644
--- a/WebCore/accessibility/AXObjectCache.cpp
+++ b/WebCore/accessibility/AXObjectCache.cpp
@@ -339,7 +339,7 @@ void AXObjectCache::notificationPostTimerFired(Timer<AXObjectCache>*)
 }
     
 #if HAVE(ACCESSIBILITY)
-void AXObjectCache::postNotification(RenderObject* renderer, const String& message, bool postToElement)
+void AXObjectCache::postNotification(RenderObject* renderer, AXNotification notification, bool postToElement)
 {
     // Notifications for text input objects are sent to that object.
     // All others are sent to the top WebArea.
@@ -367,14 +367,14 @@ void AXObjectCache::postNotification(RenderObject* renderer, const String& messa
     if (!obj)
         return;
 
-    m_notificationsToPost.append(make_pair(obj, message));
+    m_notificationsToPost.append(make_pair(obj, notification));
     if (!m_notificationPostTimer.isActive())
         m_notificationPostTimer.startOneShot(0);
 }
 
 void AXObjectCache::selectedChildrenChanged(RenderObject* renderer)
 {
-    postNotification(renderer, "AXSelectedChildrenChanged", true);
+    postNotification(renderer, AXSelectedChildrenChanged, true);
 }
 #endif
 
diff --git a/WebCore/accessibility/AXObjectCache.h b/WebCore/accessibility/AXObjectCache.h
index 5f873e00c30583a6cb7511184b521a590bb3e3e1..4105a504d791bc148601add734bd6aed517a1fbf 100644
--- a/WebCore/accessibility/AXObjectCache.h
+++ b/WebCore/accessibility/AXObjectCache.h
@@ -76,8 +76,6 @@ namespace WebCore {
 
         void detachWrapper(AccessibilityObject*);
         void attachWrapper(AccessibilityObject*);
-        void postNotification(RenderObject*, const String&, bool postToElement);
-        void postPlatformNotification(AccessibilityObject*, const String&);
         void childrenChanged(RenderObject*);
         void selectedChildrenChanged(RenderObject*);
         void handleActiveDescendantChanged(RenderObject*);
@@ -98,6 +96,21 @@ namespace WebCore {
         static void textMarkerDataForVisiblePosition(TextMarkerData&, const VisiblePosition&);
         static VisiblePosition visiblePositionForTextMarkerData(TextMarkerData&);
 
+        enum AXNotification {
+            AXCheckedStateChanged,
+            AXFocusedUIElementChanged,
+            AXLayoutComplete,
+            AXLoadComplete,
+            AXSelectedChildrenChanged,
+            AXSelectedTextChanged,
+            AXValueChanged
+        };
+        
+        void postNotification(RenderObject*, AXNotification, bool postToElement);
+
+    protected:
+        void postPlatformNotification(AccessibilityObject*, AXNotification);
+
     private:
         HashMap<AXID, RefPtr<AccessibilityObject> > m_objects;
         HashMap<RenderObject*, AXID> m_renderObjectMapping;
@@ -107,7 +120,7 @@ namespace WebCore {
         HashSet<AXID> m_idsInUse;
         
         Timer<AXObjectCache> m_notificationPostTimer;
-        Vector<pair<RefPtr<AccessibilityObject>, const String> > m_notificationsToPost;
+        Vector<pair<RefPtr<AccessibilityObject>, AXNotification> > m_notificationsToPost;
         void notificationPostTimerFired(Timer<AXObjectCache>*);
         
         AXID getAXID(AccessibilityObject*);
diff --git a/WebCore/accessibility/AccessibilityRenderObject.cpp b/WebCore/accessibility/AccessibilityRenderObject.cpp
index 3a3a138b58bbb91a23afc6f3f74e7df147fd4e2e..d19e854fdd27587d4448d96a772cbd97280e7828 100644
--- a/WebCore/accessibility/AccessibilityRenderObject.cpp
+++ b/WebCore/accessibility/AccessibilityRenderObject.cpp
@@ -2174,7 +2174,7 @@ void AccessibilityRenderObject::handleActiveDescendantChanged()
     AccessibilityRenderObject* activedescendant = static_cast<AccessibilityRenderObject*>(activeDescendant());
     
     if (activedescendant && shouldFocusActiveDescendant())
-        doc->axObjectCache()->postNotification(activedescendant->renderer(), "AXFocusedUIElementChanged", true);
+        doc->axObjectCache()->postNotification(activedescendant->renderer(), AXObjectCache::AXFocusedUIElementChanged, true);
 }
 
 
diff --git a/WebCore/accessibility/chromium/AXObjectCacheChromium.cpp b/WebCore/accessibility/chromium/AXObjectCacheChromium.cpp
index 87f55202e707f687ec5f12688558d0d723168937..c5d1dd4bdcb0206f76629f5b1d2a7535d027e1f6 100644
--- a/WebCore/accessibility/chromium/AXObjectCacheChromium.cpp
+++ b/WebCore/accessibility/chromium/AXObjectCacheChromium.cpp
@@ -43,7 +43,7 @@ void AXObjectCache::attachWrapper(AccessibilityObject*)
     // In Chromium, AccessibilityObjects are wrapped lazily.
 }
 
-void AXObjectCache::postPlatformNotification(AccessibilityObject*, const String&)
+void AXObjectCache::postPlatformNotification(AccessibilityObject*, AXNotification)
 {
 }
 
diff --git a/WebCore/accessibility/gtk/AXObjectCacheAtk.cpp b/WebCore/accessibility/gtk/AXObjectCacheAtk.cpp
index c7dde8ded5423a16e9710ba5f9a158997e0c6226..2e7ca66c239ffdde07b7e18b06e305b3ebda04e7 100644
--- a/WebCore/accessibility/gtk/AXObjectCacheAtk.cpp
+++ b/WebCore/accessibility/gtk/AXObjectCacheAtk.cpp
@@ -37,9 +37,9 @@ void AXObjectCache::attachWrapper(AccessibilityObject* obj)
     g_object_unref(atkObj);
 }
 
-void AXObjectCache::postPlatformNotification(AccessibilityObject* coreObject, const String& message)
+void AXObjectCache::postPlatformNotification(AccessibilityObject* coreObject, AXNotification notification)
 {
-    if (message == "AXCheckedStateChanged") {
+    if (notification == AXCheckedStateChanged) {
         if (!coreObject->isCheckboxOrRadio())
             return;
         g_signal_emit_by_name(coreObject->wrapper(), "state-change", "checked", coreObject->isChecked());
diff --git a/WebCore/accessibility/mac/AXObjectCacheMac.mm b/WebCore/accessibility/mac/AXObjectCacheMac.mm
index 21307bb9bcc6c0bc9382c5a895fb65824d74a6a6..f6f7bd7bd0922211bd946ec4760a76174bbe0c0a 100644
--- a/WebCore/accessibility/mac/AXObjectCacheMac.mm
+++ b/WebCore/accessibility/mac/AXObjectCacheMac.mm
@@ -51,12 +51,38 @@ void AXObjectCache::attachWrapper(AccessibilityObject* obj)
     obj->setWrapper([[AccessibilityObjectWrapper alloc] initWithAccessibilityObject:obj]);
 }
 
-void AXObjectCache::postPlatformNotification(AccessibilityObject* obj, const String& message)
+void AXObjectCache::postPlatformNotification(AccessibilityObject* obj, AXNotification notification)
 {
     if (!obj)
         return;
     
-    NSAccessibilityPostNotification(obj->wrapper(), message);
+    // Some notifications are unique to Safari and do not have NSAccessibility equivalents.
+    String macNotification;
+    switch (notification) {
+        case AXCheckedStateChanged:
+            macNotification = "AXCheckedStateChanged";
+            break;
+        case AXFocusedUIElementChanged:
+            macNotification = NSAccessibilityFocusedUIElementChangedNotification;
+            break;
+        case AXLayoutComplete:
+            macNotification = "AXLayoutComplete";
+            break;
+        case AXLoadComplete:
+            macNotification = "AXLoadComplete";
+            break;
+        case AXSelectedChildrenChanged:
+            macNotification = NSAccessibilitySelectedChildrenChangedNotification;
+            break;
+        case AXSelectedTextChanged:
+            macNotification = NSAccessibilitySelectedTextChangedNotification;
+            break;
+        case AXValueChanged:
+            macNotification = NSAccessibilityValueChangedNotification;
+            break;
+    }
+    
+    NSAccessibilityPostNotification(obj->wrapper(), macNotification);
 }
 
 void AXObjectCache::handleFocusedUIElementChanged(RenderObject*, RenderObject*)
diff --git a/WebCore/accessibility/win/AXObjectCacheWin.cpp b/WebCore/accessibility/win/AXObjectCacheWin.cpp
index 7a84cc10acbabd4673dd1ab22e5112989dea8e64..6f0620371651c8c037dd69a693ae587afaf0eebd 100644
--- a/WebCore/accessibility/win/AXObjectCacheWin.cpp
+++ b/WebCore/accessibility/win/AXObjectCacheWin.cpp
@@ -51,7 +51,7 @@ void AXObjectCache::attachWrapper(AccessibilityObject*)
     // software requests them via get_accChild.
 }
 
-void AXObjectCache::postPlatformNotification(AccessibilityObject*, const String&)
+void AXObjectCache::postPlatformNotification(AccessibilityObject*, AXNotification)
 {
 }
 
diff --git a/WebCore/dom/Document.cpp b/WebCore/dom/Document.cpp
index e0d156046fb5dc786ac60e29d340205d2d273a61..bf22d88fb4917692ef0fee75eec8522952e914c0 100644
--- a/WebCore/dom/Document.cpp
+++ b/WebCore/dom/Document.cpp
@@ -1758,7 +1758,7 @@ void Document::implicitClose()
         // exists in the cache (we ignore the return value because we don't need it here). This is 
         // only safe to call when a layout is not in progress, so it can not be used in postNotification.    
         axObjectCache()->getOrCreate(renderObject);
-        axObjectCache()->postNotification(renderObject, "AXLoadComplete", true);
+        axObjectCache()->postNotification(renderObject, AXObjectCache::AXLoadComplete, true);
     }
 #endif
 
diff --git a/WebCore/dom/Element.cpp b/WebCore/dom/Element.cpp
index 1260f9b86ae2b3b051a2648c0f7c84883d36e77f..218d6bf96f7089dffca8bb83c32cdf0965a888ab 100644
--- a/WebCore/dom/Element.cpp
+++ b/WebCore/dom/Element.cpp
@@ -602,16 +602,17 @@ void Element::attributeChanged(Attribute* attr, bool)
 
 void Element::updateAfterAttributeChanged(Attribute* attr)
 {
-    if (!document()->axObjectCache()->accessibilityEnabled())
+    AXObjectCache* axObjectCache = document()->axObjectCache();
+    if (!axObjectCache->accessibilityEnabled())
         return;
 
     const QualifiedName& attrName = attr->name();
     if (attrName == aria_activedescendantAttr) {
         // any change to aria-activedescendant attribute triggers accessibility focus change, but document focus remains intact
-        document()->axObjectCache()->handleActiveDescendantChanged(renderer());
+        axObjectCache->handleActiveDescendantChanged(renderer());
     } else if (attrName == roleAttr) {
         // the role attribute can change at any time, and the AccessibilityObject must pick up these changes
-        document()->axObjectCache()->handleAriaRoleChanged(renderer());
+        axObjectCache->handleAriaRoleChanged(renderer());
     }
 }
     
diff --git a/WebCore/editing/Editor.cpp b/WebCore/editing/Editor.cpp
index b9dfc5dd3c2c6781c4dc60d8930d1d2635c62a7f..3f3f736ec73b19460a1e2953d184fb7f271aa9c9 100644
--- a/WebCore/editing/Editor.cpp
+++ b/WebCore/editing/Editor.cpp
@@ -393,7 +393,7 @@ void Editor::respondToChangedContents(const VisibleSelection& endingSelection)
     if (AXObjectCache::accessibilityEnabled()) {
         Node* node = endingSelection.start().node();
         if (node)
-            m_frame->document()->axObjectCache()->postNotification(node->renderer(), "AXValueChanged", false);
+            m_frame->document()->axObjectCache()->postNotification(node->renderer(), AXObjectCache::AXValueChanged, false);
     }
     
     if (client())
diff --git a/WebCore/editing/mac/SelectionControllerMac.mm b/WebCore/editing/mac/SelectionControllerMac.mm
index 5970f99a5ff3222d61c12cb2fadd589e318141f4..47fb4343f103efb0b1bd66368f7b0347454cd9de 100644
--- a/WebCore/editing/mac/SelectionControllerMac.mm
+++ b/WebCore/editing/mac/SelectionControllerMac.mm
@@ -38,7 +38,7 @@ void SelectionController::notifyAccessibilityForSelectionChange()
     Document* document = m_frame->document();
 
     if (AXObjectCache::accessibilityEnabled() && m_sel.start().isNotNull() && m_sel.end().isNotNull())
-        document->axObjectCache()->postNotification(m_sel.start().node()->renderer(), "AXSelectedTextChanged", false);
+        document->axObjectCache()->postNotification(m_sel.start().node()->renderer(), AXObjectCache::AXSelectedTextChanged, false);
 
     // if zoom feature is enabled, insertion point changes should update the zoom
     if (!UAZoomEnabled() || !m_sel.isCaret())
diff --git a/WebCore/html/HTMLInputElement.cpp b/WebCore/html/HTMLInputElement.cpp
index 4ae2ec91e0d99b95301896d8ea22c7f0bae2df6e..0e98a46b5bc486bbb2ae95f60d5c41f4006252dd 100644
--- a/WebCore/html/HTMLInputElement.cpp
+++ b/WebCore/html/HTMLInputElement.cpp
@@ -1000,7 +1000,7 @@ void HTMLInputElement::setChecked(bool nowChecked, bool sendChangeEvent)
     // RenderTextView), but it's not possible to do it at the moment
     // because of the way the code is structured.
     if (renderer() && AXObjectCache::accessibilityEnabled())
-        renderer()->document()->axObjectCache()->postNotification(renderer(), "AXCheckedStateChanged", true);
+        renderer()->document()->axObjectCache()->postNotification(renderer(), AXObjectCache::AXCheckedStateChanged, true);
 
     // Only send a change event for items in the document (avoid firing during
     // parsing) and don't send a change event for a radio button that's getting
diff --git a/WebCore/page/FrameView.cpp b/WebCore/page/FrameView.cpp
index c8a0e1dab2e2a30741b3841ab9631622e5400e20..b28c32bd9637625a6c0f1ef0d62482a25a9a8735 100644
--- a/WebCore/page/FrameView.cpp
+++ b/WebCore/page/FrameView.cpp
@@ -649,7 +649,7 @@ void FrameView::layout(bool allowSubtree)
 
 #if PLATFORM(MAC)
     if (AXObjectCache::accessibilityEnabled())
-        root->document()->axObjectCache()->postNotification(root, "AXLayoutComplete", true);
+        root->document()->axObjectCache()->postNotification(root, AXObjectCache::AXLayoutComplete, true);
 #endif
 #if ENABLE(DASHBOARD_SUPPORT)
     updateDashboardRegions();
diff --git a/WebCore/rendering/RenderTextControl.cpp b/WebCore/rendering/RenderTextControl.cpp
index 72444bef0e99bead5f9d65a6e286553add283366..4f4b5703058fe2456d9d7dd3c52a857e0435d496 100644
--- a/WebCore/rendering/RenderTextControl.cpp
+++ b/WebCore/rendering/RenderTextControl.cpp
@@ -182,7 +182,7 @@ void RenderTextControl::setInnerTextValue(const String& innerTextValue)
                 frame->editor()->clearUndoRedoOperations();
                 
                 if (AXObjectCache::accessibilityEnabled())
-                    document()->axObjectCache()->postNotification(this, "AXValueChanged", false);
+                    document()->axObjectCache()->postNotification(this, AXObjectCache::AXValueChanged, false);
             }
         }