Remove custom signatures from V8 bindings

Source/bindings/v8/V8Binding.cpp

Index: Source/bindings/v8/V8Binding.cpp
diff --git a/Source/bindings/v8/V8Binding.cpp b/Source/bindings/v8/V8Binding.cpp
index 2d8da03d149da659eb13c671735f449d1a70ce70..45e6beffc7eb3a58c6f65e8e8b797bd7ed7456d6 100644
--- a/Source/bindings/v8/V8Binding.cpp
+++ b/Source/bindings/v8/V8Binding.cpp
@@ -137,6 +137,18 @@ PassRefPtr<NodeFilter> toNodeFilter(v8::Handle<v8::Value> callback, v8::Isolate*
     return filter.release();
 }
 
+DOMWindow* toNativeDOMWindow(v8::Handle<v8::Value> value, v8::Isolate* isolate)
+{
+    if (value.IsEmpty() || !value->IsObject())
+        return 0;
+
+    v8::Handle<v8::Object> global = v8::Handle<v8::Object>::Cast(value);
+    v8::Handle<v8::Object> windowWrapper = global->FindInstanceInPrototypeChain(V8Window::domTemplate(isolate, worldType(isolate)));
+    if (windowWrapper.IsEmpty())
+        return 0;
+    return V8Window::toNative(windowWrapper);
+}
+
 const int32_t kMaxInt32 = 0x7fffffff;
 const int32_t kMinInt32 = -kMaxInt32 - 1;
 const uint32_t kMaxUInt32 = 0xffffffff;