Faster access to isolated worlds.

bindings/v8/V8IsolatedWorld.h

Index: bindings/v8/V8IsolatedWorld.h
===================================================================
--- bindings/v8/V8IsolatedWorld.h	(revision 51310)
+++ bindings/v8/V8IsolatedWorld.h	(working copy)
@@ -85,7 +85,9 @@
             // worlds at all.
             if (!isolatedWorldCount)
                 return 0;
-            return getEnteredImpl();
+            if (!v8::Context::InContext())
+                return 0;
+            return reinterpret_cast<V8IsolatedWorld*>(getGlobalObject(v8::Context::GetEntered())->GetPointerFromInternalField(V8Custom::kDOMWindowEnteredIsolatedWorldIndex));
         }
 
         v8::Handle<v8::Context> context() { return m_context->get(); }
@@ -94,7 +96,10 @@
         DOMDataStore* getDOMDataStore() const { return m_domDataStore.getStore(); }
 
     private:
-        static V8IsolatedWorld* getEnteredImpl();
+        static v8::Handle<v8::Object> getGlobalObject(v8::Handle<v8::Context> context)
+        {
+            return v8::Handle<v8::Object>::Cast(context->Global()->GetPrototype());
+        }
 
         // Called by the garbage collector when our JavaScript context is about
         // to be destroyed.