Revert r174506

Source/bindings/core/v8/custom/V8WindowCustom.cpp

Index: Source/bindings/core/v8/custom/V8WindowCustom.cpp
diff --git a/Source/bindings/core/v8/custom/V8WindowCustom.cpp b/Source/bindings/core/v8/custom/V8WindowCustom.cpp
index a3d11523f1fdbaa186e50ce606ff4d7fc311b316..843f1dd05333245a94d6896667cca58be47006ca 100644
--- a/Source/bindings/core/v8/custom/V8WindowCustom.cpp
+++ b/Source/bindings/core/v8/custom/V8WindowCustom.cpp
@@ -157,7 +157,13 @@ void V8Window::eventAttributeGetterCustom(const v8::PropertyCallbackInfo<v8::Val
         return;
     }
 
-    v8::Handle<v8::Value> jsEvent = V8HiddenValue::getHiddenValue(info.GetIsolate(), info.Holder()->CreationContext()->Global(), V8HiddenValue::event(info.GetIsolate()));
+    ASSERT(frame);
+    // This is a fast path to retrieve info.Holder()->CreationContext().
+    v8::Local<v8::Context> context = toV8Context(frame, DOMWrapperWorld::current(info.GetIsolate()));
+    if (context.IsEmpty())
+        return;
+
+    v8::Handle<v8::Value> jsEvent = V8HiddenValue::getHiddenValue(info.GetIsolate(), context->Global(), V8HiddenValue::event(info.GetIsolate()));
     if (jsEvent.IsEmpty())
         return;
     v8SetReturnValue(info, jsEvent);
@@ -172,7 +178,13 @@ void V8Window::eventAttributeSetterCustom(v8::Local<v8::Value> value, const v8::
         return;
     }
 
-    V8HiddenValue::setHiddenValue(info.GetIsolate(), info.Holder()->CreationContext()->Global(), V8HiddenValue::event(info.GetIsolate()), value);
+    ASSERT(frame);
+    // This is a fast path to retrieve info.Holder()->CreationContext().
+    v8::Local<v8::Context> context = toV8Context(frame, DOMWrapperWorld::current(info.GetIsolate()));
+    if (context.IsEmpty())
+        return;
+
+    V8HiddenValue::setHiddenValue(info.GetIsolate(), context->Global(), V8HiddenValue::event(info.GetIsolate()), value);
 }
 
 void V8Window::frameElementAttributeGetterCustom(const v8::PropertyCallbackInfo<v8::Value>& info)