Make error messages for cross-domain access OOPIF-friendly.

Source/core/frame/DOMWindow.h

Index: Source/core/frame/DOMWindow.h
diff --git a/Source/core/frame/DOMWindow.h b/Source/core/frame/DOMWindow.h
index 399cec0a49383c2a42a63d2e9c9e0546c48a4dd2..96a8fd58f3db283a9bda67ca02386241581397f4 100644
--- a/Source/core/frame/DOMWindow.h
+++ b/Source/core/frame/DOMWindow.h
@@ -181,11 +181,9 @@ public:
 
     void postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, const String& targetOrigin, LocalDOMWindow* source, ExceptionState&);
 
-    // FIXME: These should be non-virtual, but this is blocked on the security
-    // origin replication work.
-    virtual String sanitizedCrossDomainAccessErrorMessage(LocalDOMWindow* callingWindow) = 0;
-    virtual String crossDomainAccessErrorMessage(LocalDOMWindow* callingWindow) = 0;
-    virtual bool isInsecureScriptAccess(DOMWindow& callingWindow, const String& urlString);
+    String sanitizedCrossDomainAccessErrorMessage(LocalDOMWindow* callingWindow);
+    String crossDomainAccessErrorMessage(LocalDOMWindow* callingWindow);
+    bool isInsecureScriptAccess(LocalDOMWindow& callingWindow, const String& urlString);
 
     // FIXME: When this DOMWindow is no longer the active DOMWindow (i.e.,
     // when its document is no longer the document that is displayed in its