Expose performance.memory in workers

Source/core/frame/Console.cpp

Index: Source/core/frame/Console.cpp
diff --git a/Source/core/frame/Console.cpp b/Source/core/frame/Console.cpp
index 6ac28f7980cca07956e8c0e8fd5aebd952996bf7..73e2ab123f219b3b9bbbf451fbd79e8a42850658 100644
--- a/Source/core/frame/Console.cpp
+++ b/Source/core/frame/Console.cpp
@@ -81,7 +81,7 @@ PassRefPtr<MemoryInfo> Console::memory() const
 {
     // FIXME: Because we create a new object here each time,
     // console.memory !== console.memory, which seems wrong.
-    return MemoryInfo::create(m_frame);
+    return MemoryInfo::create(m_frame->document());
 }
 
 } // namespace WebCore