Make DOMWrapperWorlds easier to use

Source/bindings/v8/DOMWrapperWorld.cpp

Index: Source/bindings/v8/DOMWrapperWorld.cpp
diff --git a/Source/bindings/v8/DOMWrapperWorld.cpp b/Source/bindings/v8/DOMWrapperWorld.cpp
index b469b2f149a2ca40c27b6e16f353a539f076d47b..a5e8cec381d44aafa73bf1ce567022e9a4723e0d 100644
--- a/Source/bindings/v8/DOMWrapperWorld.cpp
+++ b/Source/bindings/v8/DOMWrapperWorld.cpp
@@ -32,6 +32,7 @@
 #include "DOMWrapperWorld.h"
 
 #include "DOMDataStore.h"
+#include "ScriptExecutionContext.h"
 #include "V8Binding.h"
 #include "V8DOMActivityLogger.h"
 #include "V8DOMWindow.h"
@@ -64,6 +65,16 @@ DOMWrapperWorld::DOMWrapperWorld(int worldId, int extensionGroup)
         m_domDataStore = adoptPtr(new DOMDataStore(IsolatedWorld));
 }
 
+DOMWrapperWorld* DOMWrapperWorld::current(ScriptExecutionContext* scriptExecutionContext)
+{
+    if (scriptExecutionContext->isWorkerContext())
+        return 0;
+    ASSERT(isMainThread());
+    ASSERT(v8::Context::InContext());
+    DOMWrapperWorld* world = isolatedWorld(v8::Context::GetCurrent());
+    return world ? world : mainThreadNormalWorld();
+}
+
 DOMWrapperWorld* mainThreadNormalWorld()
 {
     ASSERT(isMainThread());